|Affiliation:||Los Angeles Police Department|
|Children:||Aaron Biehn (son)|
Don Biehn was the father of Aaron Biehn.
Before Trinity Edit
Don went to school at Cal State University Northridge.
In 1980, Don Biehn married a woman named Carianne. For their wedding, they received a fondue set that they kept, but never opened. His wife had a fondness for two antique blue lamps that Don did not like.
Don's interest was in guns. He spent time practice shooting and had the following weapons in his safe: a Heckler & Koch .40 caliber semi-automatic, a Kimber Custom II .45 caliber, and a Smith & Wesson .38 caliber six-shot revolver.
In 1986, the couple had a son named Aaron. Though Don was raised Catholic, he had no true attachment, and mainly went to Mass because it pleased his wife. Aaron didn't particularly like going to church. Don didn't know why, but assumed his son was being a baby, and forced him to go, even making him attend Sunday School.
During his first year as a homicide detective, about seven or eight years prior to the events of Trinity, Don and his partner worked a bank robbery case involving a couple of career criminals. Don managed to arrest one of them in his home. He’d found several weapons, including a Taurus 92F, and discovered that the Taurus was unregistered. Don had stashed it away, and no one had noticed. As a cop who had tracked suspects through their guns and watched prosecutors nail them with ballistics, Don figured that it useful to have a weapon unconnected to himself.
Aaron tried to tell Don that Father Frank, their priest, had sexually abused Aaron, but could not bring himself to do so. Aaron tried to kill himself whilst in the bath, but Don managed to get in in time to get him out and call an ambulance. Don found Aaron's diary and discovered about the abuse, and so went to see Frank at the rectory. He injured him, and forced him to tell Don who else abused children, and which other children had been abused. Frank eventually named Father Collins, Dortmund and Cardinal Mulrooney as others who had abused children, and Don shot him in the face.
He went to see Collins, but was abducted by Michael Shalhoub before he could do anything. Michael tortured him, but Don managed to escape. Shortly thereafter, LAPD officer Harry Driscoll arrived to arrest Don for the murder of Frank, but Don offered him a deal which altered Harry's initial reaction.
Later, Don was killed at the behest of Michael Shalhoub in St. Monica's Cathedral.