The woman as responsible as anybody for setting the case of the UC Davis "sweethearts" killings on its path toward resolution told a Sacramento Superior Court jury Wednesday how she did it.

First, criminalist Kaye Springer told the cops to bring all the evidence they had. Then she went through it, and she found a few things investigators for 12 years had not thoroughly examined.

Springer's search hit the jackpot in 1992 when it turned up four semen stains on a blanket. It took another 10 years, but the DNA in the fluids later matched Richard Joseph Hirschfield, prosecutors say.

He is on trial on double murder and rape charges and faces the death penalty in the killings of the 18-year-old victims, Sabrina Gonsalves and John Riggins.

Her hair is turning gray and she is now a grandmother two times over, but Springer clearly recalled the events of 20 years ago when Yolo County investigators brought in some fibers taken from Gonsalves' hair for her to routinely examine for trace evidence.

"After the fiber analysis, I started asking questions about what case they were using this information on, and I made the suggestion they should just look at everything," said Springer, then working as a criminalist for the state Department of Justice lab in Sacramento.

She testified she looked through pictures of all the evidence in the case and that she noticed a blanket on the floor of a van Riggins and Gonsalves had been driving the night they were killed.

"I thought that might be interesting to look at, and I asked if that might be brought in," Springer said of the blanket.

Davis Police Detective Fred Turner and Yolo County district attorney's investigator John Haynes delivered the red, white and blue "bundle up" blanket to Springer on June 22, 1992.

A couple of weeks later, she took it out of its tattered packaging and tape-lifted it for fiber samples. In the process, "I noticed some stains," she testified.

Springer said they were "yellowish," and located in four discernible spots. She testified she instructed a trainee to run a screen on them, "and they came back positive" for semen.

"I was surprised," Springer said. "I didn't really think I was looking for semen."

She notified the Yolo County District Attorney's Office of her discovery.

"I felt it was a pretty important finding," Springer said in her courtroom testimony.

Prosecutors in Yolo County were about to go forward with a murder trial on four defendants.

The case turned to ashes, however, when DNA extracted from the semen stains excluded all of the defendants. Yolo was forced to dismiss charges.

It wasn't until 2002 that the DNA lifted from the Springer search matched up with samples from Hirschfield submitted to a national data bank, Sacramento prosecutors say. Hirschfield, who is now 63, was then in prison in Washington state for the 1997 rape of a child.

But Springer wasn't finished. By 2002, she had switched over from the state DOJ to a job at the Sacramento County crime lab. About the same time the DNA analysts allegedly were finding Hirschfield's genetic profile lining up with the semen stains, Springer decided to take a look at some slides that had been sitting around for the previous 22 years.

In her scientific investigation in 1992, Springer had ordered up from a private lab some additional testing on the semen to see if it was at all mixed in with saliva.

Sure enough, the tests turned up what Springer described in her testimony as a "moderately strong" presence of an enzyme called amylase, a digestive agent found in saliva.

In her 2002 re-examination of slides taken from the slaying victims, "I was able to actually find sperm on the oral swab taken from Sabrina Gonsalves," Springer testified. She pointed it out to the jury Wednesday on a slide flashed on an overhead projector.

Assistant Public Defender David Lynch, one of three attorneys working on Hirschfield's behalf, tried to poke holes in Springer's findings in his cross-examination.

Lynch pointed out that the evidence bag containing the blanket had been torn and ripped, suggesting the possibility of contamination.

Other items of evidence, such as the victims' clothing, had been commingled, Springer confirmed under Lynch's questioning, and a vial of Riggins' blood had been broken. She never took pictures of the semen stains, and she couldn't be 100 percent certain the amylase came from saliva and not some other bodily fluid.

"It's one of many possible scenarios," Springer said, about the amylase coming from saliva, "but it's probably the most logical one."

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