FORT WORTH -- Friends described Precinct 5 Deputy Constable Mark Diebold as a consummate law enforcement officer and a great friend.

Diebold died Thursday during tactical team qualifications this morning, according to a news release from the Tarrant County Sheriff’s Department. Deputy Diebold was finishing qualifications when it appears that he had a heart attack, but the official cause of death is still unknown, the release said.

Diebold is survived by his wife and three daughters.Diebold, 48, was born June 28, 1969.

He worked for the Tarrant County Sheriff’s Department from 1994 to 2008, after which time he began working for the constable’s office.

Justice of the Peace Sergio De Leon called Diebold a gentle giant. Diebold, who worked in De Leon’s office, was the type of law enforcement officer who could face down the baddest of bad guys one moment and the next moment, help bring a child into the world, which he did.

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