Angie Dodge would have been 40 years old today. But in June 1996, when she was 18, when an unknown man brutally killed her in the middle of the night.
While Chris Tapp served two
decades in prison for participating in the murder, a slew of experts say he was wrongfully convicted after a false confession. He was released earlier this year in a resentencing deal cut with prosecutors.
What is certain is that an unknown killer has never been caught. Several DNA samples found at the crime scene, including from semen found on her body, point to the same as-yet unidentified man.
Carol Dodge, Angie’s mother, has been on a tireless crusade for more than 20 years to find her daughter’s killer. She said she sees few prospects at present.
“Nothing is moving on Angie’s case,” she said. “Nothing.”
She hopes a new technique called familial DNA searching could turn up a lead. She’s been told that Idaho officials are considering adopting the technique.
“I think this is something new,” she said. “We’ve tried everything else. It has solved nothing. It’s (soon) going to be 22 years since Angie was murdered.”
Familial searching as a technique bears some similarity to, but is fundamentally different than, the submission of the unknown killer’s DNA to Ancestry.com’s database. That submission turned up a lead suggesting the killer may have been a relative of a man named Michael Usry Sr., but subsequent tests indicate Usry is very distantly related to the killer, if at all.
Unlike in the Ancestry.com submission, where the killer’s DNA was compared against a database of people who voluntarily submitted DNA for genealogical purposes, familial searching uses the state’s existing CODIS (Combined DNA Index System) database, which contains DNA profiles from both known and unidentified offenders.
The technique is based on sociological research that tends to show “crime runs in families,” Rock Harmon said.
Harmon was for many years a prosecutor in Alameda County, Calif. He was an early advocate for familial searching, a technique that was first developed in the United Kingdom. Since retiring he spends much of his time advocating its adoption in states around the country.
Harmon said the technique is also more reliable than the Ancestry.com approach because it is backed by validation studies, where the technique is tested to make sure it successfully identifies known close male relatives and doesn’t turn up spurious matches. The DNA tests used in Ancestry.com’s database, which weren’t intended for forensic purposes, haven’t undergone similar validation studies.
Conventional CODIS searches only turn up direct matches; they check whether a submitted DNA sample is an exact match to profiles already in the database. The software used for familial searching instead takes an unidentified DNA sample and searches CODIS for profiles that are similar enough to be a possible family member, usually a father, son or brother. This first search turns up a ranked list of existing offenders in CODIS.
A certain number of those most likely matches then have their Y chromosome, which is passed from father to son mostly unaltered, tested through another DNA technique using archived samples in the state crime lab. This second test confirms or disproves that individuals on the ranked list are related to the unidentified offender.
Police then use conventional investigative techniques to identify which relatives of the person whose DNA is already in CODIS could be the source of the unidentified DNA. Police obtain DNA from those relatives to look for an exact match. This can be done through a search warrant, but Harmon said more commonly police collect “abandoned DNA” — things such as discarded cigarette butts, drinking straws or used silverware — from suspects so they aren’t tipped off.
Harmon said evaluations in the 11 states that have implemented the procedure show familial searching has a success rate similar to traditional CODIS searches — about 35 percent, using a somewhat complicated metric.
Harmon, who worked on cold cases as a prosecutor, said when investigations have failed to turn up leads using conventional police work, investigators are left relying on “lottery tickets,” such as the hope that the killer’s DNA is found in another crime.
“Familial searching is another lottery ticket that has as good of odds as CODIS,” he said.
At present, there are 562 unknown forensic profiles in Idaho’s CODIS database.
Harmon said that makes familial searching one of the more successful forensic tools when investigating cold cases. Techniques such as DNA phenotyping, which was performed on the unknown Dodge killer’s DNA to produce a projection of what the killer might look like, have resulted in some cold cases being solved. But familial searching has solved several high-profile cases since it started being used in the first states more than a decade ago.
Among these was the identification of Lonnie David Franklin Jr. as the “Grim Sleeper,” a serial killer in south Los Angeles. Franklin was convicted last year of nine murders, though he’s suspected in about 25, according to the L.A. Times. Franklin was identified through familial searching when his son’s DNA was entered into the state’s CODIS system.
“We have an opportunity,” Carol Dodge said. “It’s been proven in other states that it works. It’s possible that through this technique we could find the individual who killed Angie.”
Familial searching isn’t currently utilized in Idaho.
In every state where familial searching has been implemented, Harmon said, it’s been done in the same way. The state crime lab gets outfitted to perform necessary DNA testing on the Y chromosome, if it doesn’t already have that ability. And then there’s a legal determination that the technique conforms with existing law.
Carol Dodge said Matthew Gamette, head of the state crime lab, indicated to her that the state is considering a similar move, and that a policy is being drafted to implement it.
The Post Register’s request last month for an interview with Gamette was denied.
“Idaho State Police Forensic Services currently has neither a policy in place nor the technical ability to perform familial DNA searching,” wrote Idaho State Police spokesman Tim Marsano. “However, we are monitoring developments, policies and procedures in other states that are implementing familial DNA searching.”
Carol Dodge said she hopes the state will move to implement the procedure soon.
“It wouldn’t only help in Angie’s case,” Carol Dodge said. “Idaho has several cases that are sitting on shelves, and other victims are wondering what happened to their loved ones, too.”
Reporter Bryan Clark can be reached at 208-542-6751.
Reporter Bryan Clark can be reached at 208-542-6751.