For decades he didn't give up trying to ID a boy and his killer. The obsession paid off just before this detective retired

By Steve Almasy, CNN

(CNN) -- For years Maj. Tim Horne had a box under his desk he'd bump his leg into almost every day.

He didn't move the box, because it was in his "damn way" on purpose.

The box was stuffed full of information about a cold case of the worst kind, the killing of a child, and he just had to solve it.

The investigator for the sheriff's department in Orange County, North Carolina, put off his retirement for months, until last week, hoping he could get final answers in the 1998 killing of a 10-year-old boy.

He wanted resolution, he said, not just for the family, but for himself. He had investigated the case since the day the decomposed body was found underneath a billboard near an interstate.

"This has been my child for 20 years," he said by phone. "I needed closure also."

The boy's remains were discovered in September 1998 by a maintenance crew doing yard work. Horne came to the scene and was there for hours as the crime scene team took photos of the skull, collected the remains, and looked for other clues to identify the body and figure out why someone did this.

This week, authorities announced they had identified Robert "Bobby" Adam Whitt, born in Michigan and raised in Ohio. They said a suspect is already in custody.

"This case is an example of dogged determination of investigators who refused to give up. The efforts of Maj. Tim Horne and the entire investigation division were exemplary," Sheriff Charles Blackwood said.

A heart-wrenching mystery

The case drove at his heart from the very beginning, Horne said, because it involved a child, one who had been left out in the elements so long officers didn't immediately know whether it was a boy or a girl. Later, clothing would give them their first gender clue.

There were obstacles from the first days of the investigation, because there were no reports of missing children that matched the child. And Horne didn't know that about 200 miles away there was another body -- an adult woman who 20 years later would be identified as the boy's slain mother.

Horne, 50, said he tried to keep the boy's case in the public eye. Wherever he went he would talk about it. If he went to seminars or classes he would reach out to instructors about the case and how to solve it.

In his office, he intentionally set the box with the case file in his way. It was a reminder.

He already knew everything that was in the file, but he wanted to make sure it was on his mind.

"I didn't think I would forget the case, but I wanted to be sure," he said.

Horne also regularly drove by the billboard where the remains were found. He was hopeful he'd catch the killer coming back to check out the scene, so if there was a vehicle pulled over, Horne would wheel in and have a chat.

There were moments in the case when he grew disheartened. Despite the killing getting some national publicity, there weren't any tips that moved it in a positive direction.

A well-known forensic sculptor named Frank Bender made a 3D bust of the boy that was featured in a 2011 documentary about Bender called "The Man Who Faced Death."

Parabon NanoLabs was working with the boy's DNA.

Retirement just had to wait

In 2018, Horne had the option to retire in June after 30 years. There was no way he was leaving. Not only did he need to resolve the boy's case, but he also had another cold case, a double murder from the 1970s, that he wanted to solve.

"It was unfinished business," he said, but he still worried. "No matter how long you stay there comes a day when you have to step way."

But then new methods of looking at DNA changed the case, just as in other cases, including leading to an arrest of the suspected Golden State Killer. The new DNA results in North Carolina showed the boy was first-generation Asian-American, something investigators hadn't known.

Genealogist Barbara Rae-Venter, who also worked on the Golden State Killer case, found a probable cousin of the boy's living in Hawaii.

Horne got on the phone with that person and got some clues. He tried to find other relatives in other states. He called 20 people during his Christmas break. No one got back to him right away.

On December 26, at 1:44 p.m. -- he won't forget the time -- a call came from the 513 area code in Ohio.

Finally he had Bobby's name, just five days before his last official day. He also learned that the boy's mother, Myoung Hwa Cho, was missing, so he kept going even into the new year. He could still be a cop as he used up his remaining vacation time.

With new information, they got a hit in the database of missing cases. There was an unidentified woman who had been found along I-85 in South Carolina about the same time Bobby was discovered. A DNA comparison showed she was Bobby's mother, who was from South Korea. Authorities there helped confirm her identity.

Horne spent his last days wrapping up the other cold case, and working the final stretch of the investigation into the killings of Bobby and his mom. Horne spent more than a week in his car driving to interviews, making hundreds of calls, spending each waking minute on finishing before his retirement became official.

Finishing with names and a suspect

Horne said he couldn't talk about the ongoing parts of the case, including whether he had talked to the suspect, who is in federal prison because of another case. The suspect has not been identified by authorities nor charged in the killings.

Horne sounded exuberant but also exhausted, like a marathoner who just crossed the line.

"You almost want to collapse," he said.

But he had one last job to do, even though he's now just Jim and no longer Maj. Horne. He spent Tuesday talking to the media, telling the story about how he didn't want to give up and noting that thanks to a team effort that involved other investigators, forensic modelers, genealogy experts and DNA labs, he can move on with the rest of his life.

Horne, who has a son born a few years after the killing, isn't quite sure what he's going to do in these next years. His past 20 have been so consumed with working he hasn't really had a chance to look ahead. He knows his wife has a few things on her list.

There is one thing he looks forward to: testifying at a trial for Bobby's killer.