Wednesday 12-21-2005
Chapter 33
In the lab, Warrick carefully gloved and removed the smashed beer cans he'd recovered at the top of the water tower from the sealed brown paper evidence bags he'd carefully stored them in. First, he swabbed around the opening of each and sealed the swabs for the DNA lab. He also dumped any remaining liquid from each of the cans into a sterile evidence jar. Depending on the techniques used, fingerprinting was generally the last stage of evidence collection, short of techniques that required destruction of the object itself, as many of the methods used to recover fingerprints destroyed other evidence that might be present.
Despite his bravado with Catherine earlier, Warrick knew that generally the recovery of fingerprints from crushed cans was fairly straightforward, if time consuming and requiring of patience. And ironically, the crushed aspects of the can might have protected prints from being obliterated in the collection, transport and processing of the evidence. Gloved hands didn't LEAVE fingerprints, but they could wipe them off just as easily as anything else. So, for that matter, could rattling around in whatever container the evidence was stored in for transport.
Starting with the first can, he began to gently unfold and untwist the can. He'd chosen one of the easier ones to start with. It was accordioned in at the middle, and not crushed flat like some of the others. But the same technique would work with them, and likely he'd be able to get some good prints, if not with fingerprint powder, then with cyanoacrylate fumes. Warrick knew some labs preferred vacuum metal deposition or use of special stains over fuming for prints on non-porous surfaces, but in his book there was nothing that compared to fuming with superglue. Not that he didn't adjust and use the best technique for each situation, but he'd found that either conventional dusting or fuming virtually always worked.
By the time Warrick had unfolded the first can, he'd decided to fume the cans rather than dust them. The lab had a designated fuming chamber, but not being particularly fond of cleaning the superglue deposits off of glass, an essential job as the presence of deposits stimulated polymerization of other deposits, thereby pulling the fumes away from the items being examined, and requiring more and more superglue to get the job done, Warrick preferred fuming in a cardboard box that he could throw away once the buildup got too heavy. Normally with cans, tipping the can up and leaning it in a corner did a good job of exposing the majority of the surface area to the fumes, but with only four corners to a box, and eleven cans to be fumed, Warrick used a large paperclip tied to a string and placed crosswise inside the opening of each can to suspend them from a rod laid across the top of the carton.
He carefully put a small dish of single layer aluminum foil on the coffee warmer at the bottom of the box and placed a nickel-sized glob of superglue in the middle. He also placed a cup of hot water in the box, and, against the wall off to one side, an additional piece of aluminum foil with a test print he'd made by rubbing his thumb on the side of his nose and then pressing it onto the foil.
Closing the box, Warrick turned on the cup warmer and set a timer for five minutes. While it fumed, he quickly ran the swabs he'd collected around the corner to the DNA lab. When the timer dinged, he checked the test print to make sure the deposition of cyanoacrylate wasn't too heavy, then set the timer for another five minutes. This time, when it chimed, he turned off the heating element and checked the test print again. Perfect! Now, to see what he'd found…