Fifty-three years after a private plane carrying five men disappeared on a snowy Vermont night, experts believe they have found the wreckage of the long-lost jet in Lake Champlain.

The corporate jet disappeared shortly after departing the Burlington airport for Providence, Rhode Island, on Jan. 27, 1971. Those aboard included two crew members and three employees of the Atlanta, Georgia, development company Cousin’s Properties, who were working on a development project in Burlington.

Initial searches for the 10-seat Jet Commander turned up no wreckage and the lake, which 400 feet at its deepest point, froze over four days after the plane was lost. At least 17 other searches happened, until underwater searcher Garry Kozak and a team using a remotely operated vehicle last month found wreckage of a jet with the same custom paint scheme in the lake close to where the radio control tower had last tracked the plane before it disappeared. Sonar images were taken of the wreck found in 200 feet near Juniper Island. The island is slightly more than 3 miles southwest of Burlington.

“With all those pieces of evidence, we’re 99% absolutely sure,” Kozak said Monday.

The discovery of the wreckage in Lake Champlain, which is sandwiched between New York and Vermont, gives the families of the victims “some closure and answers a lot of the questions they had,” he said.

Kozak told CBS affiliate WCAX-TV that the search may have taken so long because jets break up into many pieces that aren’t easy to spot.

“A jet, it looks like a pile of rocks, literally. So, to most people looking at sonar data, they can overlook it because they’ll go, ‘Oh, that looks like geology,” Kozak told the station.

According to his website, Kozak’s career in undersea search and survey began in 1972 and his company specializes in shipwreck and aircraft location. In 2012, Kozak was a member of a team that discovered a World War II-era German submarine in waters off Nantucket.

While relatives are grateful and relieved that the plane has been found, the discovery also opens up more questions and old wounds.

“To have this found now … it’s peaceful feeling, at the same time it’s a very sad feeling,” Barbara Nikita, niece of pilot George Nikita, said in an interview with The Associated Press on Tuesday. “We know what happened. We’ve seen a couple of photos. We’re struggling I think with that now.”

Frank Wilder’s father, also Frank Wilder, was a passenger on the plane.

“Spending 53 years not knowing if the plane was in the lake or maybe on a mountainside around there somewhere was distressing,” said Wilder, who lives outside if Philadelphia. “And again, I’m feeling relieved that I know where the plane is now but unfortunately it’s opening other questions and we have to work on those now.”

When the ice melted in the spring of 1971, debris from the plane was found on Shelburne Point, according to Kozak. An underwater search in May of 1971 was unable to find the wreckage. At least 17 other searches happened, including in 2014, according to Kozak. At that time, authorities were spurred by curiosity after the Malaysia Airlines plane disappearance that year with the hope that new technology would find the wreck but it did not.

Barbara Nikita, who lives in southern California and her cousin Kristina Nikita Coffey, who lives in Tennessee, spearheaded recent search efforts and contacted other victims’ relatives.

What was fascinating in reconnecting with the group was “everybody had pieces of the pie and the puzzle that when we started sharing information and sharing documents what we got was a much greater both understanding and perspective of the information, how we were all impacted by this,” said Charles Williams, whose father, Robert Ransom Williams III, an employee of Cousin’s Properties, was on the plane.

The National Transportation Safety Board is investigating to verify if it is the plane, Williams said. The NTSB doesn’t do salvage operations, which would be expensive, Williams said.

“Whether there is tangible remains, and I hate to say it that way, and worth disturbing that’s a decision that we’ll have to figure out later, and part of what we’re unpacking now,” he said. “It’s hard when you start to think about that.”

The relatives of the victims plan to hold a memorial now that they know where the plane is located.

The announcement of the dicovery comes about 10 months after wreckage from a Tuskegee airman’s plane that crashed during a World War II training mission was recovered from Lake Huron.