No Way Out

by David Kessler

  “So why do you need to get the original source code if you can do that?”

  “Two reasons. First of all, the original source code often has fields and arrays with self-explanatory names like jurorName and jurorList. When the source code is compiled into machine code, these self-explanatory names are lost and replaced with digital numbers. If you then decompile the source code, you don’t get the original names back. Instead you get more technical sounding names generated by the decompiler, like TextField01 or Array01.”

  “I see,” said Alex, barely understanding.

  “The other thing is that the source code usually has explanatory notes. Those notes can help some one reading the original source code to understand the program. But the notes are ignored by the compiler, or rather discarded completely. So that when you decompile the machine code, it doesn’t recover the explanatory notes.”

  “How does the compiler know to ignore the explanatory notes when it’s compiling the original source code?”

  “They’re sandwiched between special characters. Those characters flag the compiler to ignore them when generating the machine code.”

  “Okay well we’ll try and get the source code at the hearing on Friday. Gotta go now. They’re going back into court.”

  Thursday, 20 August 2009 – 11:10

  “The morning session of the trial got off to a pretty uneventful start today, with police doctor Elaine Weiner testifying about her initial examination of Bethel Newton.”

  While David was talking to his son, Martine Yin was delivering her report facing Lake Merritt on the grass triangle between 12th and 14th Street in front of the main entrance to the Alameda County Court House. To her left and right were other news vans, from other stations, doing their reports.

  “Though some observers expected experienced criminal attorney Alex Sedaka to conduct a probing cross-examination, testing Dr Weiner on her recollections of the events, especially after the withering questioning faced by alleged victim Bethel Newton yesterday, Sedaka chose instead to waive cross-examination altogether.”

  The white stone façade of the majestic court building provided the backdrop as she continued to outline the events that had occurred in the courtroom minutes before. Her report would be accompanied by pictures by the press artist that had been scanned in the broadcast truck and transmitted to the TV station.

  “It is not clear if this marks a change in his courtroom strategy or simply a recognition that some evidence stands on too solid ground to be worth challenging.”

  The young man who had followed her yesterday was watching nonchalantly, from the corner of Fallon and 12th Street.

  “It should be stressed, that at no stage did Dr Weiner’s testimony directly implicate the defendant, Elias Claymore. But it was used by the prosecution to establish chain of custody over the DNA evidence which is to be presented later today.

  “Martine Yin, Eyewitness News, Alameda County Court House.”

  She smiled at the lanky cameraman, but noticed that he was looking unhappy.

  “Okay we had some cloud cover bang in the middle there. It may have screwed up the lighting. Do you think we can do the bit about waiving cross examination again?”

  “We haven’t got time. They’re going to start again, any minute.”

  “Okay in that case we’ll get a bite to eat and get back here for the lunch-time adjournment.”

  And with that the cameraman and soundman got into the van and drove off. Rather foolishly Martine decided to walk across the grass to get back to the court building. However, even though she was wearing practical shoes, all it took was one misstep and she ended up losing her balance. It was not exactly flat on her face, but rather awkwardly on her side, taking it on her left arm. To their credit, the other news crews didn’t laugh or even smile. They just looked away with embarrassed smirks on their faces. Martine sensed their reactions and felt a stab of anger, or at least irritation. But she took a deep breath and rose above it.

  She looked at her left sleeve. There was no mistaking it: the mud was visible on the blue, and wiping it would make no difference She could do the report in her blouse and snooker waist coat. But then she looked at her matching blue skirt and saw that it too had traces of mud. She could get them to do the lunch time report medium close or mid shot. She might even have time to put in a call on her cell phone to get them to bring a change of clothes.

  But then she realized that her face and makeup were also a bit of a mess. She had her purse checked in at the court cloakroom. And they had makeup in the van. But she realized that she needed a complete change. She had a change of clothes in her car. But that was parked at the parking structure two blocks away. There was a kind of pecking order for parking cars in the vicinity of the court. The judge’s park there cars around the court itself. The lawyers tended to park in the parking lot of the nearby Oakland Museum. Reporters, witnesses and relatives of those involved in the cases parked in the parking structure two blocks away. That was where Martine would have to go during the lunch-time adjournment to change in her car.

  But then she realized another problem. At the lunch time adjournment, all the other reporters would do their reports immediately. If she delayed hers to walk two blocks, take the elevator up four levels, change and then walk back, she’d be filing her report a lot later than the rest – and well away from the hour that a headline story like this merited. Also, if she rushed, she’d be glistening and nervous. The glistening could be taken care of with makeup, but not the nervousness.

  She could phone the camera crew and ask them to stop by at the parking structure and tell them what to get. But she’d still have to change in the van and that would take time. Also, she didn’t feel comfortable now. She wanted to change immediately.

  She looked at her watch again. She still had seven or eight minutes – and they never return from the recess bang on the dot. She knew that if she walked briskly, she could get to her car, freshen up, change clothes and still be back before they got to the substantive questions. They always started off with preliminary questions to establish the experts credentials and she knew that this time would be no different.

  So she set off down 12th Street for the parking structure, two blocks away, unaware of the man who was walking a few yards ahead of her.

  Thursday, 20 August 2009 – 11:20

  “All rise!” said a bailiff as the judge returned. When the judge was seated, the others followed suit.

  Alex was tense when the court reconvened after the short recess. He knew that they were now about to hear the crucial make-or-break portion of the prosecution’s evidence.

  “Are you ready to proceed, Ms Jensen?” asked the judge.

  “Yes, Your Honor,” said the prosecutor. “My next witness is Doctor Victor Alvarez.”

  A bailiff opened the doors to the witness anteroom and said: “Call Victor Alvarez!”

  Victor Alvarez, a man in his sixties with an air of the academic about him, entered the courtroom. He was in fact the Technical Leader of the DNA section of the Ventura crime lab and had done the analysis himself because it was such a high-profile case. He was sworn in and then asked a few preliminary questions to establish his qualifications and the fact that he worked at the lab where the DNA profiling was done. This was followed up by a detailed explanation of what DNA is, using the DOAR Digital Evidence Presentation System to illustrate his testimony with a series of diagrams and pictures – all delivered in his “wise old expert” tone.

  He explained that DNA is made up of four so-called “bases,” referred to by the letters A, C, G and T, and that these bases formed pairs, but only in a very specific ways.

  “A always pairs with T,” he explained, “and C can only pair with G.”

  When he fell silent from this preliminary explanation, Sarah Jensen was ready to move on.

  “Now could you explain how you use this to identify the source of the DNA?”

  “There are certain particular sequences of DNA that vary a lot
from one person to another. It is these sequences that we use for DNA analysis in criminal detection.”

  “And how do you do this?”

  “We look for something called Short Tandem Repeats, or STR for short. These are short sequences of DNA, normally of length two to five bases. These short sequences are in turn repeated between six and fifteen times at particular locations or loci. For example, a sequence like–”

  He clicked to show the next chart. It showed a sequence of letters:

  G-A-T-A-G-A-T-A-G-A-T-A-G-A-T-A-G-A-T-A-G-A-T-A

  “That’s a sequence of four bases at a location known as D7S280. In this case there are six repetitions of the sequence G-A-T-A. Such a repeated sequence is called an allele. At each location you have a pair of alleles – as we call them – which might be either the same or different. So a person might have the GATA sequence six times in one allele and eight times at the other. Or they might have identical sequences at both alleles.”

  “And how does this help identify the person?”

  “Well different people have different numbers of repetitions of that particular sequence. In this particular case it can vary between six and fifteen repetitions.”

  “But between six and fifteen means only ten possibilities?”

  “Yes indeed.”

  “So there must be lots of people who match that particular sequence?”

  “Yes indeed. But we don’t look at just that one sequence. We look at thirteen different sequences. For any one sequence, many people may have the same number of repetitions. But once you start looking at all thirteen different sequences at different locations, then the likelihood of two people having the same number of repetitions as each other in each of the various sequences is extremely small. But the problem is that sometimes the amount of DNA in the evidence sample is extremely small.”

  “So how do you deal with that?”

  “By increasing the quantity.”

  Thursday, 20 August 2009 – 11:30

  Martine took the elevator to the fourth level of the parking structure feeling tense and flustered at the amount of time it had taken her to get here. She knew that the trial would have already started, but there was nothing she could do. She just hoped that she could get one of the stringers from the print press to fill her in on anything that she had missed.

  There was nothing unusual to alert Martine as the elevator doors opened and she walked over towards her car. Parking structures held no fear for her, at least not in daylight. And there was plenty of daylight seeping in from the periphery to complement the strip lighting.

  She pressed her combination on the remote key to open the car, ignoring the man moving things about on the front passenger seat of his aquamarine Mercedes in the adjacent parking spot. At the back of her mind, was the recollection that Elias Claymore’s missing car – like the one used in the rape of Bethel Newton – was the same make and color. And this man was…

  She dismissed the thought, opened the driver’s door and slid into her car. She was just about to close the driver’s door when the man standing on the passenger side of the adjacent car lurched at her, shoved her hard into the passenger seat and slammed the door behind him. Before she could scream, he clamped an iron right hand over her mouth, his thumb under her jaw holding it shut. With his free left hand, he operated the mechanism to incline the seat back until it was almost horizontal. Then he started ripping at her clothes.

  In those few seconds, terror truly engulfed Martine. They were high up, on the fourth level of the parking structure, so people were less likely to come here than to the lower levels and wouldn’t hear her outside on the street. It was not the beginning or the end of lunch-time so this would not be a key time for people to arrive here or leave. And this man was holding her down, so that she couldn’t be seen by others on this level, even if anybody came. Also he was strong and easily able to withstand her pathetic attempts at resistance.

  Her skirt had by this stage been hitched up and her panties and pantyhose ripped off completely. He was now struggling with his own clothes and Martine could feel from the contact between them that he was already aroused physically as well as psychologically. The only thing she didn’t know, as she struggled to reach into her pocket, was whether he intended to let her live when he was finished with her.

  Thursday, 20 August 2009 – 11:40

  “So Polymerase Chain Reaction is a method of increasing the amount of DNA available for testing?”

  Sarah Jensen was continuing her direct examination of Victor Alvarez.

  “That’s right.”

  “And how does it work?”

  Alvarez pressed on the button to show an animation that he could speed up or slow down as he illustrated the process graphically.

  “It involves heating and cooling the DNA in a special chamber called a thermal cycler, together with certain other chemicals called enzymes. This causes the DNA to unravel and split into separate strands and then each strand forms a new pair of strands with the other chemicals in the same way as it does in the body, with the bases forming pairs like I said before.”

  “And how many times do you do this?”

  “It can be anything from twenty-eight cycles to thirty-four. Each cycle doubles the amount of DNA.”

  “But once you’ve got enough DNA for testing, how do you distinguish between DNA from the victim and DNA from the perpetrator of the crime?”

  “We start off by defining threshold quantities. Anything that shows up in the test in a smaller quantity is simply treated as noise and therefore ignored. Then we look at the relative quantities of what’s left to identify what we call the ‘major contributor’ and the ‘minor contributor’. Next we compare the evidence sample to the victim’s reference sample to determine if the victim is the major or the minor contributor. We do the same with the suspect’s reference sample to see if the suspect matches the other contributor. If we find a sequence in the evidence sample that matches one found in the suspect’s reference sample, then we call that an inclusion. The more inclusions we find, the more likely it is that the suspect is the source of that DNA. On the other hand, if we find even one sequence that can’t be matched to the suspect or the victim, then we would call that an exclusion.”

  “And how many exclusions does it take to exclude a suspect completely?”

  “All it takes is one.”

  Sarah Jensen paused and turned to the jury, to make sure that this had registered. They set their bar high to include a suspect, and proportionately low to exclude him.

  “Now you spoke about the major and the minor contributor. Does that mean that the DNA in the evidence sample is always a mixture?”

  “Not always. We can isolate the DNA from sperm using a method called Differential Extraction. We tried that in this case with DNA from a vaginal swab. But unfortunately, in this case, it turned out that there was no sperm in the sample. We then compared the DNA from another vaginal swab to the reference samples of both Bethel Newton and Elias Claymore.”

  “And what did that show?”

  “The test showed that it contained DNA from Bethel Newton but not from Mr Claymore or indeed anyone else.”

  “And does exclude Mr Claymore?”

  “No, it’s only an exclusion when the evidence sample does contain a mixture of DNA from more than one contributor. In this case, all the DNA came from Miss Newton, so that doesn’t eliminate anyone.”

  “But how do you explain it the absence of any DNA from another contributor?”

  “Well, in itself it’s consistent with two explanations. One is the absence of sexual activity. The other is use of a condom.”

  “So what did you do then?”

  “We then turned our attention to the nail clipping samples from when Miss Newton scratched the victim.”

  Thursday, 20 August 2009 – 11:45

  Martine was gasping for breath now, struggling against the man’s weight upon her. He had now unfastened his belt and pants and for a brief, fleeting moment
he lifted his weight off her so that he could pull them down. It gave her the chance she needed. Quick as a flash, she twisted her body and pulled out the small pepper spray canister. She knew, from her limited training, not to waste any time or effort trying to carefully position the canister. That would merely telegraph her intentions. She swung it close to his face, closed her eyes, held her breath and let out a large burst of spray,

  The man cried out in agony and anger, twisting away from her onto the driver’s seat and rubbing his eyes – the very thing that one is not supposed to do. Martine herself was gasping and coughing from the back spray. She sat up, to make it harder for him to resume his assault and at the same time grabbed his throat, digging her thumb hard into the soft tissue. He let out another cry of pain, but this time managed to deliver a vicious punch to the side of her face. She was dazed by the force of the punch, but in some way it helped as it made her forget the discomfort of the back spray that was affecting her.

  As she recoiled, she grabbed the handle of the front passenger door and tugged at it. Then she remembered that it had a security lock. Fortunately, she knew where everything in the car was. She pressed a button under the dashboard and the passenger door was unlocked. On her second attempt she managed to operate the door mechanism and open the door, but before she could push it wide enough to effect her escape, the man grabbed her arm again. She let out a scream of “fire!” remembering the old rule that people were more likely to respond to the word “fire” than “help.”

  He silenced her by placing his hand firmly over her mouth. But it was the same hand that he had used to grab her arm – his other hand was still rubbing his burning eyes. With her arms and hands free, she pushed the passenger door open wider with one hand while using her other – reinforced by a powerful biting action of her teeth – to remove his hand from her mouth. Again he cried out in pain and retracted his hand to suck on the wound and the toothmarks.

  Without waiting for him to make another move, she twisted away through the open door and ran out of the car continuing to scream “fire!”