Not long after he left his Minnesota home in 1976, 16-year-old James “Jimmie” Byron Haakenson called his mom to tell her he was doing OK in Chicago.

That was the last she ever heard of him.

Now, more than 40 years later, authorities believe that call might have been placed from one of the Chicago area’s darkest places: the northwest suburban ranch-style house where serial killer John Wayne Gacy lived.

On Wednesday, Cook County Sheriff Tom Dart identified the teenager as one of Gacy’s 33 victims, with sheriff’s officials confirming his remains based on a DNA sample recently submitted by his family.

Gacy was executed in 1994. A total of 26 bodies were found in his crawlspace. With Haakenson’s remains now identified, only six of those victims remain unidentified.

Haakenson’s mother came to Chicago to see if her missing son was among the victims as word of Gacy’s atrocities spread. But she had no dental records — the method investigators relied on at the time — so her son remained known as Victim No. 24 for decades.

“Jimmie’s mother always wanted to try to find out what had happened to her son,” said Dart, noting that she passed away several years ago.

Haakenson’s family in Minnesota plans to come to Chicago to mark his grave.

“One of the worst people in the world that walked the earth murdered my brother,” his sister, Lori Sisterman, who lives in North St. Paul, said Wednesday.

“You hope for something different,” but she went on to add, “I’m so glad to know where my brother is.”

In March of this year, one of Haakenson’s nephews who’d heard the story of his uncle began searching the Internet for clues on what might have happened to him.

He came across information about how the Cook County Sheriff’s Department was using DNA samples from relatives of missing people to see if any of the unidentified remains found in Gacy’s basement matched.

Haakenson’s relatives turned in samples, and “it was an immediate hit,” Dart said Wednesday.

Jason Moran, a sheriff’s detective who’s been working the case, traveled to Minnesota and arrived at the home of Sisterman on Tuesday.

“They knew I was coming to see them for a reason. But hearing the words is what hurts,” Moran said, noting that is was an emotional, tear-filled day.

“Jimmie was an incredibly special kid. His family loved him intensely,” Dart said.

Haakenson is the second of the eight Gacy victims to be identified since Dart ordered his investigators to reopen the cases in 2011.

“Now we are down to six unidentified,” Dart said.

Dart said that Haakenson was found in a stack of three bodies.

The body on top of Haakenson was identified long ago as that of 17-year-old Rick Johnston, who disappeared Aug. 6, 1976, after attending a concert at the Aragon Ballroom — around the same time Haakenson went missing.

Dart said the time frame may shed light on when the third, unidentified body, went missing and urged anyone with a relative who went missing in the Chicago area around that time to reach out to his office and submit a DNA sample.

“We’re asking people to please come forward,” he said.

Months after Dart initially had the bodies exhumed in 2011, his office announced that it had identified one of the victims as William George Bundy, a 19-year-old construction worker.

The investigation has also solved four cold cases that were not related to Gacy, locating five missing persons who were still alive and two who had died elsewhere in the U.S. For example, in 2013, Dart announced that thanks to the DNA collection in the Gacy case, investigators were able to identify remains found in a wooded area in New Jersey as a teenager who ran away from a nearby orphanage in 1972.

Gacy is remembered as one of history’s most bizarre killers, largely because of his work as an amateur clown. Gacy, a Chicago-area building contractor, lured young men to his home by impersonating a police officer or promising them construction work. There, he stabbed one and strangled the others before he buried most of them in the crawlspace or dumped the others in a river.

Contributing: Associated Press