Charles Moose, a former Maryland police chief who led the investigation of the 2002 D.C. sniper attacks, has died at 68.

According to his former agency, the Montgomery County Police Department, Moose passed away at his home on Thanksgiving.

“We are extremely saddened by the news announcing the passing of former Chief Charles Moose,” current Montgomery Chief Marcus Jones said. “He was a great leader and led our department through the D.C. sniper investigation, one of the most difficult crime sprees in our country’s history. We send condolences to his wife Sandy and all of his family and friends.”

Moose was praised as a hero for leading the multi-agency response to the sniper attacks, collaborating with the ATF, the FBI, the U.S. Secret Service, and the Virginia Department of Transportation during the investigation.

Police eventually tracked down and arrested the suspects, John Allen Muhammed and Lee Boyd Malvo. Over the course of 10 months, the snipers killed seventeen people and wounded ten others, and was widely covered by the media.

Muhammed was put to death in 2009, while Malvo is serving a life in prison.

Before moving to Maryland, Moose also made history as the first Black police chief in Portland, Oregon.

“I am deeply saddened by the death of Chief Charles Moose last night, who led PPB in the 1990s,” Portland Police Chief Chuck Lovell tweeted. “I feel connected to Chief Moose as he was the first African-American chief, a champion of community policing and led the Bureau during challenging times.”

Moose, who earned a Ph.D. and a veteran of the Air National Guard, wrote a book about the sniper investigation titled “Three Weeks in October.”