DNA evidence taken from a 10-year-old rape case may have proven that there is no physical evidence linking Lodi resident Peter Rose to the crime, but finding the real rapist will be much more difficult.
Investigators have turned over the DNA to a state crime lab in Richmond, where scientists will hopefully be able to establish a genetic "profile," said San Joaquin County Deputy District Attorney Brian Short. That profile will then be compared with samples in a DNA database of convicted felons.
But there's no guarantee that the scientists will come up with a match -- or even be able to find enough DNA to do a proper match.
"There's enough evidence to say, 'These chromosomes don't match.' But they might not be able to make a full DNA profile," said Short, who is now investigating the Nov. 29, 1994 rape of a 13-year-old Lodi girl.
It sometimes takes only a few chromosomes to prove that two DNA samples don't match, said Gary Sims, case work director at the California Department of Justice's DNA lab in Richmond.
"You can often exclude someone if you can just get a few results," Sims said.
However, there's a major league difference between finding a few chromosomes and building a profile that will accurately identify someone as a suspect.
In the Lodi rape case, scientists were able to prove that Rose's DNA did not match the evidence.
It was enough proof for Judge Stephen Demetras to vacate his conviction on Oct. 29 and order that Rose be immediately released from Mule Creek State Prison in Ione. Rose, now 36, had spent 10 years behind bars.
Prosecutors have until Jan. 7 to decide whether to retry Rose, and Short said he wants to do more investigation on the case before making such a decision.
Short's first goal had been to find the victim who had identified Rose as her attacker, only after hours of police interviews.
Short has since spoken with the victim, now 23, who has recanted her trial testimony, saying she does not know who her rapist was and never even saw his face.
The next goal for Short is to find her boyfriend from 10 years ago and see if the DNA matches him.
At the time of the assault, the girl told investigators that she had showered, put on clean clothes and headed toward a school bus stop shortly before she was dragged into an alley off the 400 block of Eden Street.
Although that could imply that the only evidence should be that of the girl and her attacker, Short wants to rule out the boyfriend, whom investigators have not yet located.
If the DNA matches him, it would point to more inconsistencies in the girl's testimony, but would also leave a bigger problem for prosecutors.
"It would then be a dead end and we'd have a really hard time finding another suspect," Short said.
The DNA is being analyzed at the Richmond lab, where scientists are working on about 100 cases at any given time, Sims said.
He could not comment on the Rose case specifically, but said it generally takes several weeks for scientists to put together a DNA profile. Occasionally, they can focus more efforts on one case if it's a special situation or there is a stiff court deadline.
Short said the lab officials are aware of the Jan. 7 deadline.
"It's still very iffy if we're going to be able to get an actual profile. Right now, we don't have that," he said.
Each person has about 3 billion pairs of chromosomes, and not all of them are useful in determining identity, Sims said. For instance, he said, the genes that determine that a person will have two arms are not going to help link a suspect to a crime.
If scientists do have enough specific DNA, they will compare it to a state database of samples taken from about 275,000 felons who were convicted of certain crimes ranging from rape to felony spousal abuse to carjacking.
Additionally, the samples will be compared to a "forensic index" of about 9,000 other open cases. In comparing DNA to those cases, scientists have sometimes linked crimes even if they don't identify suspects, Sims said.
Short is hoping to see some kind of result, but if not, the suspect will likely be a "big question mark."
Contact reporter Layla Bohm at email@example.com.