BOONE, N.C. -- Watauga County deputy William Mast was killed last week during a shoot-out with a man at a home in Deep Gap, and on Tuesday hundreds of law enforcement officers from around the country came to pay their respects as he was laid to rest.

It was a somber scene at the Mt. Vernon Baptist Church in Boone. The mountains formed a peaceful backdrop, and an United States flag hung high above, with two fire trucks supporting it.

Just below, hundreds of law enforcement officers from around the country stood at attention. Hundreds more followed behind the caisson carrying the flag-draped coffin of the 23-year-old killed last week responding to a 911 call.

Around 1:15 a.m. Thursday, Mast went to Hardin Road off U.S. 421 about eight miles northeast of downtown Boone, after dispatchers received a 911 call from a home there. No one spoke when the call was answered, authorities said.

When Mast arrived, 33-year-old Mitchell Allen Trivette opened fire, striking Mast, authorities said.

Another deputy returned fire, killing Trivette. Both Mast and Trivette died as a result of their injuries.

Authorities have not revealed what might have led Trivette to shoot the deputy, and a search of public records revealed Trivette had no criminal convictions in North Carolina.

Mast’s parents walked just behind their son’s coffin Tuesday. His widow, Paige Mast, is eight months pregnant with the couple’s first child. She joined the procession midway.

“The pain is almost unbearable,” said Regina Alford. “He was a doting husband and he would have been a doting father. I first met William when he was a freshman at Watauga High. He always had a bright smile. He was just a delight to be around.”

Mast and his widow were high school sweethearts, together for 10 years and would have celebrated their second wedding anniversary Thursday.

Alford said she was honored to see the law enforcement that came from across the country for the funeral. “A heavy heart. He will be missed so very badly,” she added.

He’ll be missed perhaps most of all by the son he’ll never know – a baby boy due next month already named after his father.

Mast’s family has asked that, in lieu of flowers, memorials be made to a fund for his son: the William Hunter Mast Scholarship Fund, in care of Highland Union Bank at 1013 N.C. 105, Boone, NC 28607.

The Charlotte Observer contributed.