CLEVELAND, Tenn. - Judy Dillon didn't recognize the truck that pulled into her driveway in late spring, but the police badges caught her eye as she peeped through the blinds.

The 68-year-old Cleveland woman tried to imagine who was in trouble as she opened her door and asked: "Are you'uns coming to take me to jail?"

It wasn't until the detectives asked if she was Stacy Dillon's mom that she realized why they were there.

After 21 years, Judy had given up hope that anyone would be interested in solving her son's murder. She had come to terms with what she believed was a botched police job.

Over the years she had watched television shows where cold cases were solved, giving her some hope. She had finally found peace that her son's killer would pay for his sins in the afterlife.

So when detectives told Dillon that her son's murder case had been reopened, she didn't know what to say. She didn't know how to feel.

The lights were off on March 17, 1991, when Judy was driven to her Cleveland home. She had visited family in California to give her 22-year-old son a break from taking care of her. She had been bedridden after major knee surgery.

It was just the two of them in their one-story home. Judy had moved Stacy to Cleveland when he was 11. He continued to live with his mother as he commuted to the University of Tennessee at Chattanooga to study marine biology, working part-time jobs to pay for school. He kept to himself and only had a few close friends.

That evening when Judy Dillon's friend, who had driven her home, knocked on the door, no one answered. Dillon heard a shriek when her friend turned the lock and stepped inside. Bolting out of the house, her friend ran around the yard in circles before collapsing on the seat next to Dillon.

"What is it? What is it?" she asked. "Is he breathing? Is there blood?"

He couldn't tell her that her only child was lying on his back in the hallway with a bullet wound through his cheek.

After police ruled he son's death a homicide, snapped pictures, collected evidence and hauled her son's body away, she was left with unanswered questions.

A murder weapon was never found. The medical examiner didn't conduct an autopsy.

For months it became a ritual for Judy to hobble to the jail with a walker and ask police for an update on the case. But she said police offered few answers.

Weeks after Stacy Dillon was buried, his mother found out there had been no autopsy. She thought about exhuming the body in hopes of getting answers but, at the advice of a counselor, she decided it would be too difficult to have her son's body dug up.

One day when she visited police, they gave her a box of her son's possessions that had been taken for evidence. When she opened the box, inside was a phone handset still covered in her son's blood. She screamed.

Finally, Judy stopped going to the jail altogether. She heard from detectives less and less.

She never went back inside her home after Stacy Dillon's death. She stayed with friends until she could rent a new apartment.

• • •

For years, Stacy Dillon's case files sat in storage. A Tennessee Bureau of Investigation agent looked at the case in 1998, but nothing came of it. Police looked again in the early 2000s with no movement.

It didn't get another look until Lt. Mark Gibson opened the file in September 2011. The Cleveland Police Department was working on its national accreditation and detectives were required to review cold cases and decide if there was any chance they could be solved.

This case was difficult. There was no autopsy. Evidence was missing. Some records didn't match up. There were few photos.

But as Gibson continued reading through the files, he thought he could build a solid case. So he took Stacy Dillon's file with him when he went to the FBI Academy later in the fall. He needed advice on where to start on a 21-year-old case.

Detectives were able to identify people to talk with and a person of interest, the same man police had looked into more than 20 years before.

• • •

Former Cleveland Police Chief Arnold Botts defends the first investigation, saying investigators had a person of interest, but the suspect hired an attorney and refused to be interviewed.

Police couldn't test for DNA on fingerprints at the time and the case went cold, Botts said.

"You have very little to work with," he recalled.

Six months after Stacy's death, Botts resigned as police chief in the middle of a federal investigation that was sealed after the chief left.

Over the years, Judy has blamed a distracted department that was under scrutiny for never solving the case. But Botts said that isn't true.

"I could understand her frustration," he said. "There was diligent effort placed on the part of the investigators."

Today, Gibson admits the case was overlooked in many areas. He has started to re-interview family and friends and investigate new tips coming in. Police also have sent off skin cells for DNA.

"This could be a solvable case," he said. "But it's going to depend on who's available to come forward."

• • •

The night Stacy Dillon died, he was on the phone with a friend, family members and police said.

He told his friend he was worried about someone and needed advice. But before he could finish, someone pulled in his driveway.

When police found him, he was wearing pajama bottoms. He was lying in the hallway next to a phone. The door was secure and the windows were intact.

Officers estimated he had been dead for three to four days, detectives said. A recorder that Stacy had purchased was missing, police and family say.

During the original investigation, police looked into Stacy's sexual orientation, Judy Dillon said, and accused her of not knowing her own son. But she didn't -- and still doesn't -- believe her son was gay.

Gibson believes he is getting closer to prove the killer was someone with whom Stacy Dillon was in a relationship. But he's not ready to make an arrest.

Meanwhile, Judy Dillon is hopeful police will find the answers she has been waiting for. But in some ways she has already received comfort.

"Even if it never goes to court or if it goes to court and he walks free, I can't express how thrilled I am that these guys remembered Stacy Dillon," she said. "They remembered my son."