A Bucks County couple and their two children died of apparent carbon monoxide poisoning Monday when the husband committed suicide by leaving his car running in the garage and the others were overcome by the fumes.

According to Pennsylvania state police, troopers responded around 11:20 p.m. to find the four family members - identified as Gary Reitnauer, 59; his wife, Michele, 58; and daughters Kimberly, 16, and Jamie, 10 - inside a residence on Kumry Road in Milford Township. None could be revived, police said.

Kimberly Reitnauer was a junior at Quakertown High School, and Jamie a fifth grader at Trumbauersville Elementary, according to a statement on the Quakertown Community School District website.

According to accounts from Bucks County District Attorney David Heckler and a state police spokesman, Gary Reitnauer went into the garage Monday night and broke the latch on the door so that no one else could get in. He then started his car and left it running.

At some point, authorities said, his wife tried to break into the garage by smashing a window with a hammer, but was overcome by the fumes. Kimberly and Jamie were found dead in the house, police said.

Police said the coroner's office would make a final determination of death. A message left with the coroner's office Tuesday afternoon was not immediately returned.

According to the school district's statement, Kimberly Reitnauer received the top possible score on the Advanced Placement calculus exam at the end of her sophomore year, and took calculus-based physics courses at Bucks County Community College during the last two summers.

She was also a trumpet player, the statement said, and was to leave Wednesday for a trip to Erie with the high school's jazz band. She was also set to play trumpet in the orchestra in the school's forthcoming musical, and she sang soprano in the school's choir.

"There is not a kid in the music department who will not be touched by her passing," choir director Jonathan Lechner said in the statement. "She was a high-energy, high-achieving, vivacious person."

Jamie, the statement said, "was following in her sister's footsteps," adding that she was on the Reading Olympics Team, played in the school band, and sang in the school chorus.

Contact Chris Palmer at 609-217-8305, cpalmer@phillynews.com, or on Twitter @cs_palmer.