Photo: Lakeland Police

Linda Patterson Slaten

On the morning of September 4, 1981, police responded to an apartment in Lakeland, Florida, to find a grisly scene.

Most disturbing: The woman’s two sons, 15-year-old Jeff and 12-year-old Tim, were asleep in the other room.

For nearly 40 years, the sons have dealt with the emotional fallout from that tragic night. “I saw the crime scene. It’s still burned in my brain today,” Tim Slaten said at a Thursday news conference.

Frustratingly, the case went cold, and it appeared that the murder would never be solved.

“It’s been rough on me my whole life not knowing who it is,” Jeff Slaten said at the news conference, ABC News reports. “Always being scared to death I was friends with him. Always looking over our shoulder.”

The case remained an open investigation. Then, in 2018, the Florida Department of Law Enforcement called the Lakeland Police Department and asked if they wanted to send DNA from the crime scene for further testing.

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Polk County Jail

Joseph Clinton Mills

The resulting report indicated that the person who most likely killed Slaten was Joseph Mills, according to an arrest affidavit filed with the Polk County Clerk of Courts.

According to court documents, Mills told police that he had consensual “wild” sex with Slaten, but denied having killed her. But police believe that he is responsible for her death, and court documents claim that the scene indicated signs of a struggle.

The arrest has left Slaten’s family reeling: “He was my football coach,” Tim Slaten, now 50, told reporters on Thursday, according toThe Ledger. “I trusted this man.”

Mills has not yet entered a plea and will be arraigned on January 21. The public defender’s office did not immediately return PEOPLE’s call for comment.

source: people.com