Mom of 7’s killing was mystery for years, until cigarette offered a clue, WA cops say

More than two decades after a mother of seven was killed, her case has finally been closed, Washington deputies said.

A 69-year-old man, who was convicted in a separate 2005 killing and is currently serving a life sentence in Arizona, was identified as a suspect in the death of Tamara (“Tammy”) Mattson, the Island County Sheriff’s Office said in a Jan. 9 Facebook post.

However, as he “suffers from advanced dementia,” deputies said the man cannot be prosecuted.

Body found

The 39-year-old mother’s body was found “dumped in vegetation at Camano Island State Park on December 9, 2003,” deputies said.

Though detectives followed up on leads and “interviewed ever-widening circles of acquaintances,” deputies said “they kept running into dead ends.”

Police found and collected a cigarette butt in a parking lot “not far from where Ms. Mattson’s body was found,” deputies said.

At the time of Matton’s death, however, DNA technology was limited.

But that changed in 2009, when “DNA technology allowed the Washington State Patrol Crime Lab to develop DNA profiles from minute amounts of human biological material,” according to deputies.

After testing the “minuscule (DNA) sample” from the cigarette butt, it was found to be a match in the Combined DNA Index System to the man imprisoned in Arizona, deputies said.

“Until scientists found the match, (the man) had been unknown to Sheriff’s detectives,” deputies said.

Though detectives now had a DNA match, deputies said they faced another problem: “How to prove that his presence in the park was at the exact time of the murder, and, moreover, that he was the murderer, and not just a witness or a bystander.”

A decade without answers

Investigators spent the next decade trying to “learn everything they could about (the suspect)” and how he might have been connected to Mattson, according to deputies.

Detective Shawn Warwick and Detective Ed Wallace threw themselves into the case, but “what little they learned was uncertain and often came from unreliable sources,” deputies said.

The detectives “decided the only play left was to interrogate (the man)” in Arizona in November 2019, deputies said.

When they met him, though, he “refused to answer any questions and demanded to be returned to his prison cell,” deputies said.

Then, the COVID-19 pandemic hit, and, for 15 more months, “the investigation all but stalled out.”

Case ‘re-animated’

But then in April 2021, the imprisoned man sent a letter to detectives that “re-animated the case.”

In his letter, he said he had information about Mattson’s death, deputies said.

“In exchange for a long list of demands, he offered to provide information about the murder,” deputies said.

The detectives brought the letter to Island County Prosecutor Greg Banks.

“Of all his crazy demands, the only one I considered was to allow him to spend the rest of his life in a Washington prison, if he turned out to be the murderer, and pleaded guilty,” Banks said in the release.

Banks arranged a “free talk” with the man, deputies said.

During the conversation, investigators could question him “under a temporary grant of immunity,” according to deputies.

“Without his confession, we were stuck,” Banks said. “This allowed him to speak candidly and allowed us to verify that he was the killer before we would negotiate any kind of deal.”

In June 2021, Banks, Warwick and Wallace interviewed the man.

This time, he “cooperated and answered all the questions put to him,” deputies said.

The trio left the prison “confident that they had found Tammy’s murderer,” deputies said.

“He knew things that only the killer and detectives knew,” Wallace said.

More than that, deputies said “he filled in gaps and explained his motive: he killed her over a dispute about a drug deal.”

The man agreed that once a prison transfer was finalized “with Arizona and Washington Departments of Corrections, (he) would sign a sworn and verified confession, covering all of the information from the ‘free talk,’” deputies said.

Finally, “with the confession in hand,” Banks could charge him “with premeditated murder in the first degree and kidnapping in the first degree,” deputies said.

More delays

But, per state protocols, their agreement was not possible.

A convicted inmate from another state can be brought to face charges in a different state, deputies said.

However, after trial, the inmate must return to the original state to finish serving their sentence before they can be sent back to another state, deputies said.

Thus, if the man pleaded guilty, he would have to return to Arizona, deputies said.

“Without a guarantee that he could stay in Washington, (he) would not sign the confession,” deputies said. “Without (his) confession, there was no proof he was the murderer, and he could not be charged.”

Neither correction agency would bend.

“I rattled all the cages I could,” Banks said.

Then, in the fall of 2024, an extradition official told Banks the agencies might be willing to work something out.

Again, Banks tried to negotiate with the suspect, “but his attempts to contact him were met with silence,” deputies said.

Then, in October, the man’s family member told Banks that he “had suffered a series of debilitating strokes and had advanced dementia.”

As such, she doubted he “could read or understand the content of the letters.”

Two months later, Banks got confirmation from Arizona prison officials that the man has “advanced dementia and is confined to a Special Needs Unit.”

Though the suspect’s “mental condition renders him incapable of being prosecuted,” Banks said he is “certain” the man is responsible for Mattson’s death, deputies said.

While Banks said “it was frustrating that they could not make a legal record of (his) crimes, at least he and detectives were able to give some measure of closure to Tammy’s family.”