Ballard headed down the aisle that ran along the endcaps, looking for the 2005 row. She found it and turned the wheel to move the shelves and open the row. She ticked a fingernail along the spines of the murder books until she found case 05-0243 and slid it out. The Laura Wilson case was contained in one overstuffed binder, which Ballard knew she would immediately reinstall in two binders to make flipping through the documents easier. She double-checked that there was not a second binder misplaced nearby during the shelving and saw that none of the other binders on the shelf carried the same case number.

She stepped out of the row and cranked it closed again, thinking all the while about how Bosch called the archives the “library of lost souls.” If that was true, she had one of those lost souls in her hand.

Back at her workstation, Ballard emailed the grant app first, then opened the thick binder she had brought from the archives. Because the origin of the DNA in the case was so unusual, she went straight to the forensics section to see how it came to be that DNA was extracted from urine.

A summary statement from the lead investigator told the story. The victim was murdered in her home, where she lived alone. The crime scene investigators noticed that the toilet seat in the bathroom off the bedroom was up, indicating that a man had used it. While checking the toilet seat and flush handle for fingerprints, a criminalist noticed urine droplets on the rim of the bowl. These drops were reddish brown in color, indicating the possibility of blood cells in the urine. The droplets were collected on swabs, and DNA extraction was conducted the same day because of the fear of possible DNA decay. A partial profile was established and then entered into the CODIS database, drawing no matches.

The summary went on to state that further analysis and medical consultation by investigators determined that the urine had come from someone who had kidney or bladder disease, causing hematuria, the medical term for blood in the urine.

Ballard was excited by what she had read and eager to see whether the investigators used the confirmation of kidney disease as an angle of investigation. Had they looked for a suspect among men being treated for kidney disease? She opened the bottom drawer of her desk and pulled out two empty binders. She removed all the documents and plastic sleeves from the original murder book, split the stack, and slipped each half onto the rings of a new binder. She then got up and went to the kitchen to get coffee before she settled in to read the case’s investigative chronology.