Follow CBSPHILLY Facebook Twitter

RICHBORO, Pa. (CBS/AP) — Authorities say a young couple found dead in their Churchville home last week died from multiple stab wounds and were both shot after they had been killed.

READ MORE: Police Release Surveillance Video Of Suspect, 2 Others Wanted In Connection To Murder Of 30-Year-Old Roynell Phavor Houston

Bucks County prosecutors announced the autopsy findings for 27-year-old Tyler Roy and 28-year-old Christina Roy on Monday. They were killed April 30 in their Northampton Township home.

Diana Taylor Charged In Connection With Death Of 2-Year-Old Girl Found Unresponsive Inside Philly Home 

Authorities haven’t found any connection between the couple and their suspected killer, 26-year-old Daniel Mooney. He died of a drug overdose on the day the bodies were found by a house painter.

Photo of Daniel Mooney, left, and Tyler and Christina Roy. (credit: Bucks County DA’s Office)

The rifle Mooney allegedly used to shoot the couple belonged to Tyler Roy.

READ MORE: King Of Prussia Businesses Provide Free Meals To Police, Fire, EMS Personnel During First Responders Appreciation Week

Authorities say Mooney gained entry through an unlocked door of a home on the 100 block of Kitty Knight Drive. Police believe that the murders happened sometime in the overnight hours.

Firefighters Rescue 2 Women Hanging From Window In Collingswood House Fire 

“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,” said Greg Shore with the Bucks County District Attorney’s Office.

Police said Mooney stayed in the house for an unknown period of time afterward.

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

MORE NEWS: Phillies Bring Back Bobby Dickerson As Infield Coach

(© Copyright 2018 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)