The last surviving family member of the worst mass murder in Bucks County history has died.

Michael Abt, 72, of Penndel, died Aug. 23 at St. Mary Medical Center in Middletown after a brief illness and a long difficult life following the murders of his parents, three siblings and a family friend 50 years ago.

In his later years, Abt said that he felt his life ended the day his family were murdered in their Trevose home, but he just didn't stop breathing. He was 21 when his family was killed.

"You're never right after something like that," he said in one of his last interviews earlier this year.

What happened on March 12, 1976 inside the Fleetwood Avenue home destroyed any possibility of Michael ever to love and commit to long-term relationships, said Linda McGonigle, the mother of Abt’s son, also named Michael. He also has a daughter with his former wife.

“He was a good man deep within, but he could not let himself feel that or let anyone who loved him be close for a long period of time,” McGonigle said. “It is very sad for the two families he left behind, especially his children.” 

“He was a character,” Allahand said. “Everything was an adventure.” 

One day when they were 14 and 15, Allahand and Abt were hanging out at the nearby Neshaminy train tracks when a freight train stopped. 

“You thinking what I’m thinking?” he recalled Michael said.

The two hopped into a freight car. They had no idea where they were going or how they’d get home.  

The two didn't speak again for seven years.

They reconnected in January, 1976 when Allahand's mom died. Michael Abt came to the house to offer his condolences. The two ended up drinking beer at a New Jersey bar.

Two months later, Allahand showed up at the Fleetwood Avenue home to console Michael after learning his family was murdered.

A Bensalem police officer found the six bodies and the dog in the basement. They were all fatally shot, a shocking crime that terrorized the quiet Trevose community.

Ten days later, a neighbor and childhood friend of Michael and his older brother, Clifford— George Geshwendt —confessed to the murders telling police his true targets were the surviving Abt brothers.   

Geschwendt was found guilty of six counts of first-degree murder and sentenced to death, later commuted to life without parole. He died in 2020 at age 68.

With his family gone, Michael filled the gaping hole in his world with sketchy people, including members of Breed, an outlaw motorcycle group that ran methamphetamines distribution in the 1970s. 

Retired Bensalem police officer David Clee, the neighbor who found the Abt bodies, said after losing his family Michael’s life took a dark turn that led to disagreements between them.  

“I do have sympathies for Mike and he was misled after that happened. I have always felt bad for him," Clee said. “He lost his childhood. He lost everything."

Former newspaper reporter Kathryn Canavan met Michael Abt when she was assigned to cover the murders and trial.  The two reconnected while she was researching her book, “Killer in the House: 10 Days of Terror in a Pennsylvania Suburb,” which was released earlier this year.   

Michael Abt attended local book signings with Caravan, where he gleefully autographed copies and reconnected with old neighbors from Trevose.

“The trajectory of Michael’s life was caused by one person,” Canavan said. “One evil act and how many lives were forked because of it.” 

Michael acknowledged he carried deep mental scars and used drugs and alcohol to cope, choices that led to financial trouble, jail time, homelessness and estrangement for most of his life.  

Michael J. Abt was preceded in death by his parents, John “Jack,” 49, and Margaret "Peggy" (Haney), 48, sisters Margie, 19, and Kathy, 12, brother Johnny Jr., 13, and brother Clifford Abt who died in 1989 at age 37. 

He is survived by his two children, an uncle on his mother’s side, cousins and many friends.  A private burial and memorial service is planned for a future date.

Crime and Courts Reporter Jo Ciavaglia can be reached at jciavaglia@gannett.com