06/21/2012 07:33 pm ET Updated Jun 22, 2012

Keith Zunke's Remains Found 30 Years After His Disappearance In Umatilla National Forest

The last three decades have been long and hard for Rebecca Carroll, but closure may be beginning for her.

On Oct. 24, 1981, Carroll's 21-year-old son, Keith Zunke, went on a trip to the Umatilla National Forest in Oregon, with fellow residents of a group home for the developmentally disabled. He got lost and was never found.

That is, until last summer when a group of hikers came upon human remains that were just confirmed as Zunke's by the U.S. Forest Service and the Oregon State Medical Examiner's Office, according to KNDO-TV.

"Family members were notified that DNA tests performed by the Oregon State Medical Examiner's forensic anthropologist confirmed the remains found near Deduct Pond are those of 21-year-old Keith Zunke," Dave Thompson, law enforcement officer for the Umatilla National Forest, told KNDO.

Carroll is still processing the news and wasn't ready to comment.

"The case is still active, so I think a statement is inappropriate at this time," she told The Huffington Post.

At the time of his disappearance, Zunke, who reportedly had the mentality of a 5-year-old because an injury at birth, was living at Stonecreek Lodge, a group home for the developmentally disabled that has since closed.

The disappearance occurred on a field trip. Carroll alleged in a lawsuit that the group was on a hike when Zunke and two other members of his group were allowed to walk back to their vehicle unsupervised.

Carroll initially asked for $500,000 in damages but told The Huffington Post she never pursued the lawsuit.

Although Zunke's remains were found last year, officials first did a thorough investigation to ensure the area was not a Native American burial site.

"We were concerned it may have been a historic Native American burial site and followed Native American Graves Protection and Repatriation Act protocol to preserve and protect the site and findings," Thompson told KNDO-TV.

He also said that he investigated past missing persons cases, but, because of the time lapse since the disappearance, he found contacting individuals with direct knowledge of the search and rescue efforts difficult.

In addition, Thompson said when he did his inital search, Zunke was not listed on the U.S. Department of Justice National Missing Persons database apparently because he had been declared legally dead in 1983 and removed from it.

However, Todd Matthews, the Communications and Outreach Manager for the National Missing & Unidentified Persons System (NamUs), said Zunke was listed in NamUs and was not removed. His case has since been archived as identified.

Because Zunke's remains were incomplete, a cause of death cannot be determined. Still, Thompson is relieved he could help Zunke's family in some small way.

"I am grateful we could finally bring closure to the family of Keith Zunke," he said.

CORRECTION: A previous version of this post incorrectly stated that Zunke's records were not in the missing person's database. In fact, Thomson was simply unable to find the record when he searched the database initially.