DNA leads to charges in Whittier, Lyndale cold cases

Forensic scientist Dr. Christine Clouser works at the Hennepin County Sheriff’s Office crime lab.

Cold cases from the early ’90s in Whittier and Lyndale suddenly saw murder charges over the last three months. In the 1993 Lyndale case, investigators sent crime scene DNA to a genealogist to find suspects, then trailed a suspect to a hockey game and picked his napkin out of the trash to test his DNA. In the Whittier case, a suspect first interviewed in 1991 was told that additional DNA testing further linked him to the apartment crime scene. His alleged response: “My DNA is there, I did it.”

DNA provides key evidence in a wide range of cases. In the past four weeks, for example, police warrants for DNA swabs in Minneapolis included a suspected arson at a downtown apartment, a road rage call that led to drugs and a gun, a sexual assault of a 14-year-old youth, and a garage burglary linked to other thefts through DNA on a spray can and an abandoned flashlight.

Hennepin County Attorney Mike Freeman said investigators use DNA evidence to both convict and clear suspects.

“Because if we don’t have a match, we don’t have a case,” he said at a recent press conference.

Freeman charged Isanti resident Jerry Arnold Westrom, age 52, in the 1993 murder of Jeanie Childs at the 3100 block of Pillsbury Avenue South. According to the complaint, an unknown DNA sample recovered from the scene was entered into commercial genealogy websites to develop suspects. Investigators trailed Westrom to a hockey game and watched him order a hot dog and wipe his mouth with a napkin, which they retrieved from the trash for testing, Freeman said. After Westrom was taken into custody, the Minnesota Bureau of Criminal Apprehension reportedly determined his DNA matched samples found on the crime scene’s comforter and bathroom towel. Westrom denied ever being at the apartment, said he didn’t recognize Childs, and said he didn’t know why his DNA would be at the scene, according to the complaint.

Freeman said the strategy is inspired by the investigation of the Golden State Killer, which uploaded the alleged serial offender’s profile to the genealogy website GEDmatch.

“We all learned quite a bit from the Golden State Killer,” said Freeman, who said he discussed the case with the district attorney in Ventura County. “I said, you know I bet we’ve got some cases back home we could use this on. Well we just found one.”

In the California case, a genealogy search found the suspect’s closest relatives were third cousins, investigator Paul Holes said in an interview with KTVU. Starting with shared ancestors born in the early 1800s, they combed through the family lineage, looking for men born at the right time with the right build with a presence in California. Then they went into traditional investigatory mode, interviewing acquaintances and quietly lifting DNA samples from the suspect’s trash can and car door handle. In the 44 years and thousand tips prior to the genealogy search, they “weren’t even close” to the suspect, Holes said. Then the genealogy search took four months, he said.

“I believe that if we had not employed this genetic genealogy tool, it’s entirely possible this case would have gone unsolved,” he told KTVU.

Testing DNA samples from the trash is not unusual, according to staff at the Hennepin County Sheriff’s Office crime lab at 6th & Park.

Minneapolis contracts with the BCA for its DNA testing, and Hennepin County receives about 2,000 requests annually from surrounding cities. Both labs are accredited. The recent cold case investigations came out of case review collaboration between the Minneapolis Police Department, the Minneapolis division of the FBI and the BCA.

Investigators can run unidentified DNA samples through CODIS, the Combined DNA Index System that contains more than 13 million federal, state and local profiles. In Minnesota, DNA from convicted felony offenders joins the database, according to the BCA. Investigators can also use the database to identify suspects through family members.

Much of the DNA testing at the Hennepin County lab relates to property crimes, which are traditionally hard to solve, said Jim Liberty, the lab’s forensic science supervisor.

“We have an incredibly high solve rate when we have DNA evidence. Eighty percent of the property crime samples we get in that are unknown, we eventually get a hit to a CODIS individual,” he said.

The county’s technology has advanced to detect about 10 DNA cells — in a drop of blood there are millions of cells, Liberty said. Equipment has become sensitive enough to track DNA traveling between people, as through shaking hands. Anything in contact with the mouth provides a particularly good sample, such as food, a drink bottle or a cigarette butt. Investigators can use surveillance video to note items a suspect has touched, then go in for a DNA sample.

Jim Liberty, forensic science supervisor at the Hennepin County Sheriff’s Office crime lab, talks with forensic scientist Dr. Christine Clouser.

“Human beings constantly are shedding their DNA into the environment. All the time, everywhere, everybody,” Liberty said, adding that some shed more than others, perhaps due to touching the mouth or sloughing more skin cells.

The lab can almost always recover DNA on guns, Liberty said. Guns are probably their No. 1 growing item of evidence, but they often hold the most complex DNA mixes to decipher, he said.

“DNA persists for a relatively long time, so whoever handled that gun at any time in the past may still have their DNA on there,” Liberty said. “And guns usually are handled by many many people, so guns are problematic because they have so much DNA.”

The lab is currently adding new robotic equipment to further automate the work, and the lab uses a new workflow to speed up processing of sexual assault kits.

More detailed and automated sequencing technology is “right at the doorstep,” Liberty said, which will identify hundreds of thousands of genetic variations, rather than the blocks of DNA identified today.

At the state BCA, lab technicians can analyze mitochondrial DNA in old and degraded samples, which is useful in cases with unidentified remains.

While DNA can quickly degrade outside in sunlight, it can remain stable for long periods when stored in dry, cool conditions, Liberty said.

Some raise concerns about the use of DNA evidence. The American Civil Liberties Union has advocated for privacy in genetic information, opposing DNA swabs related to minor offenses and opposing states that share the DNA of people arrested and not yet convicted.

The National Institute of Justice suggests that defense attorneys weigh alternative explanations for DNA at a scene, such as prior contact, transfer by touch or lab contamination, according to a 2012 report.

Attorney Thomas Kelly is representing Donald Clifton Jenkins Jr., who is charged in the 1991 murder of Belinda Thompson at the 2800 block of Grand Avenue South.

“DNA has been as useful for the defendants as it has been for the prosecuting authorities,” Kelly said. “The science seems to be very close to being impeccable and reliable, and it’s been accepted in all courts. … It’s far better than, for example, the polygraph.”

Lyndale neighborhood resident Luther Krueger recalled that 1993 was a pivotal year for volunteer crime prevention efforts, although he doesn’t remember the Lyndale cold case.

“Regrettably back then more than one homicide a year wasn’t uncommon,” he said in an email. “…With a case like this the community learns how much technology has improved, and I’d expect fewer cases will go cold for so long in this era.”