ALBANY, N.Y. — A dentist from New York who helped a U.S. organization search for American servicemen missing from World War II died after making a final scuba dive to explore a wartime plane wreck site in the English Channel, his dental practice partner said Wednesday.

The coroner’s office for Kent, England, confirmed to The Associated Press that Dr. Bruce Hottum, 63, of Glenford, New York, died last week. An investigation is underway.

The United Kingdom’s Maritime and Coastguard Agency said it was contacted Friday afternoon by a dive boat 10 miles (16 kilometers) east of Ramsgate reporting a diver needing medical aid. A helicopter was dispatched to the boat, and Hottum was airlifted to a hospital. Police in Kent, on England’s southeast coast, said Hottum was pronounced dead at the hospital.

Dr. Charles Fliegler, Hottum’s longtime partner at their dental practice in Kingston in New York’s Hudson Valley, said Hottum went to England two weeks ago after receiving a call from the group Project Recover asking if he wanted to explore a World War II plane wreck site in the English Channel that could contain human remains.

“He came up on the last dive, didn’t feel well and collapsed,” Fliegler told the AP.

Hottum was a member of local ski patrols and a certified emergency medical technician who trained other EMTs and firefighters, according to the practice’s website. He helped identify remains using dental records after the Sept. 11 terrorist attacks, Fliegler said.

“He was busy helping and going into the community. He was a good guy all the way around,” Fliegler said.

In recent years, Hottum became interested in efforts to locate, recover and identify the remains of U.S. World War II servicemen listed as missing in action. In the fall of 2015, he went to the Palau Islands in the Pacific with The BentProp Project, a Woodland, California-based nonprofit that researches World War II wreck sites and searches for American MIAs.

Fliegler said Hottum went to England to explore an underwater wreck site with Project Recover, a World War II research partnership involving BentProp, the University of Delaware and the University of California San Diego.

Numerous messages left with BentProp and Project Recover weren’t returned.

Hottum’s wife and three adult sons traveled to England to await the release of his body so he can be brought back home for burial, Fliegler said.