BOISE — For 15 years, Boise Police Detective Mark Ayotte has kept Kay Lynn Jackson's files on his desk. He felt the unsolved murder as a heavy and constant weight.
In 1999, Ayotte told the Idaho Statesman that he had faith that DNA evidence would one day lead to her killer.
Ayotte's DNA prophecy proved true. After more than 1,000 leads came up empty, it was a DNA "profile" that finally broke the case, police said Wednesday.
"We have been waiting 15 years for this day," said Deputy Chief Pete Ritter.
State police scientists have spent the past couple of years entering a backlog of DNA samples from Idaho criminals into a national database. They got a hit on one of the samples; on Monday, a grand jury indicted Patrick Jon Zacharias, a state prison inmate, in the 1998 rape and murder of Jackson.
The 22-year-old was killed on April 5, Palm Sunday morning, under the Americana Boulevard Bridge. She was walking to church after getting off work.
Zacharias, 40, has been in prison since February 2007, serving a life sentence for lewd conduct with a girl under 11. He was transferred on Tuesday to the Ada County Jail, where he was served an arrest warrant and charged with rape and first-degree murder. He is scheduled for arraignment Friday.
"The maximum penalty for first-degree murder is life in prison unless the state seeks the death penalty," said Jan Bennetts, chief of staff for the Ada County Prosecutor's Office. "That is a decision which this office does not take lightly. And we have not yet made that decision."
WHITTLING THE BACKLOG
During the initial investigation into Jackson's murder, investigators sent DNA from the suspected killer's semen to law enforcement databases around the country. They got no results.
When Zacharias was processed into prison in 2007 for the lewd conduct case, officials collected a DNA sample from him and sent it to ISP.
The Idaho DNA Database Act of 1996 requires that people convicted of certain felonies, including lewd conduct with a minor, provide a DNA sample to be catalogued into local and national databases.
In October 2010, the Idaho State Police said it had a backlog of 6,000 DNA samples to be processed into the National DNA Index Systems database. Those 6,000 samples dated to 2006 - including the sample from Zacharias.
Between then and 2012, aided by federal grants and additional state funding, ISP had new employees trained and new equipment dedicated to the backlog.
By this summer, ISP scientists will have finished the nearly three-year effort to enter more than 9,000 samples into the national database - the 6,000 DNA samples from before October 2010 and nearly 3,000 samples since.
A state law goes into effect July 1 that requires a DNA sample from everyone convicted of a felony, which means that the state will see an increase in the number of samples to be collected and processed.
50 'HITS' SO FAR
Today, nearly 12,500 Idaho samples are in the national database - nearly three times the number of samples in 2010.
Since ISP began uploading DNA collected from criminals or at crime scenes into a national database in 2002, it has received 50 "hits" - a sample that matches another DNA sample already in the database, said Cyndi Cunnington, ISP forensic scientist and biology supervisor.
DNA can lead police to a suspect, and it also can exonerate someone who's already convicted.
Charles Fain spent 18 years on Idaho's death row before a DNA test in 2001 cleared him in the 1983 killing of a 9-year-old Nampa girl.
Cynthia Sewell: 377-6428, Twitter: @CynthiaSewell