NORTHAMPTON TOWNSHIP, Pa. (CBS) — Authorities say the Daniel Mooney, the person of interest named in the double murder of a married couple in Churchville was found dead on Wednesday.

“Daniel Mooney was pronounced dead this morning… [he died] as a result of a drug overdose,” said Greg Shore with the Bucks County District Attorney’s Office.

Shore says Mooney gain entry through an unlocked door of a home on the 100 block of Kitty Knight Drive and killed 28-year-old Tyler Roy and his wife, 27-year-old Christina Roy earlier this week.

“Our team is unequivocally convinced that he killed the victims and he acted alone. Both victims have been stabbed multiple times and both victims were shot. It’s clear there was a struggle in the upstairs of the home,” Shore said.

Detectives now outside of the home of deceased suspect Daniel Kenneth Mooney’s family located adjacent from where young couple was killed. (@CBSPhilly) pic.twitter.com/Gda9iIMNz5 — Alexandria Hoff (@AlexandriaHoff) May 2, 2018

The couple’s bodies were discovered by a painter on Tuesday morning inside their home. There were no signs of forced entry.

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On Wednesday morning, the Roys’ Ford Edge SUV was found in Northeast Philadelphia, along with Mooney’s cell phone.

Shore says they don’t believe there was any prior relationship between Mooney and the victims, but they did live in the same neighborhood.

“The only relationship we are aware of is that they live in the same neighborhood,” said Shore.

Northampton Township Police Chief Michael Clark said the Roys bought their home in 2016.

“They seemed to be a nice young couple that just happened to be unfortunate victims in this case,” said Clark.

Neighbor Eileen Bily says the couple kept to themselves.

“They worked so we didn’t see much of them during the day,” said Bily.

Shore says Tyler was a construction estimator and Christina worked as a photographer.

“Clearly vibrant lives have been lost as a result of this tragedy. This tragedy is unfathomable to all of us and we pray for the victims and pray with the victims’ families,’ Shore said.

CBS3 confirms Philadelphia police officers were actively involved in the search for Mooney as they combed C Street and Indiana Avenue in the Kensington section of the city. Police have been searching well-known drug spots in the city.

“He struggled growing up. He had some mental health issues,” said Tom Walsh, who grew up with Mooney.

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Walsh says he’s not surprised he’s wanted for questioning and has a theory about what happened to the Roy family.

“I think he probably was trying to burglarize the house and didn’t realize someone was home and things went south,” said Walsh.

Police believe that the murders happened sometime in the overnight hours on Tuesday. A rifle and casings were found in the home.

An autopsy is scheduled for Thursday to determine the couples’ exact cause of death.