The blood samples from the basement were established to have come from two different individuals. A match with Sally Wilkes was made late that afternoon, but the second sample would take longer because it was more degraded. Hair samples from the suspect’s bathroom were a DNA match with the semen found in Sally Wilkes. The police had their case. They just didn’t have Walter. The secretary at Allied Heating and Cooling was their one tenuous link, so Sam phoned the owner, who gave him a Burrows Street address. They drove down and invited her to come back to the station for a conversation. Walter’s cell phone had been found in Half Moon Bay, and the last call received had been from Allied. Thus it was made clear to Mary Plant that her refusal to cooperate would guarantee a charge of obstructing justice. She was left in a holding room while Sam and the lieutenant debated the wisdom of letting Ellen conduct the interview. “The current theory is that the secretary’s got a letch for our suspect,”
