The crazed killer in a mass murder-suicide in Pennsylvania was a grandfather who slaughtered nine of his own loved ones, including his young grandchildren and a daughter days away from giving birth again, according to horrified relatives.

The 45-year-old suspect, who has yet to be fully identified, was found dead from a self-inflicted gunshot in the family home in Erie late Friday, with the murder weapon beside him, officials told Erie News Now.

After a shooting spree inside the house, he had stepped outside to gun down two women, ages 51 and 37, who rushed to the scene, before going back inside and killing himself, according to cops.

The dead included Angelina Stone, the killer’s pregnant daughter who was days away from giving birth to a third child, Kryie, who was on Saturday added to the death toll, taking it to 10. Her two other kids — son Isiah, 5, and daughter Amari’anna, almost 2 — were also killed.

“Angelina’s father killed Angelina and her children in a murder-suicide, and now our family is facing the painful task of laying them to rest,” said an online fundraiser that had collected almost $24,000 by Sunday.

The fundraiser did not otherwise identify the killer dad, who has also not yet been identified by authorities.

But the father of one of Angelina’s slain children also told Erie News Now that the killer was his one-time partner’s dad

“It was my baby, bro, and he just took her,” Ezekiel said. “Her name was Amari’anna. She’s the most beautiful baby God could have created.”

Stone had already named her unborn child Kyrie, and was due to deliver him on Wednesday.

“She was pregnant, about to have a baby in a couple of days and she had a daughter that was almost two, and her son Isaiah, who I believe was four or five,” Ezekiel’s sister Lisa Simmers told the outlet.

“They are all just beautiful children and definitely did not deserve what happened to them.”

Erie cops have yet to suggest a motive, and said Sunday that identifications were being held because “surviving family members are still being notified.”

Another fundraising website had been set up for Lora Roberts, who organizers said was among those murdered.

Roberts was remembered as “a loving mother of five, a devoted fiancée, a cherished daughter, family member, and friend to so many,” by organizers Kellie Eggleston and Christine Tombaugh.

The mass shooting unfolded shortly before 5 p.m. on Friday in a home on the 700 block of Perry Road on the East Side of the lakeside city of 91,000 between New York and Ohio.

Investigators uncovered video and audio evidence that showed gunshots were fired in the home before two “distressed” woman began pounding on the door of the house, police said.

The 45-year-old family patriarch came outside and shot them dead before going back into the house, according to authorities.

When cops arrived, they found the bodies of the women, ages 37 and 51, outside. After deploying a drone and a robot during a non-violent standoff, they entered the house to find the bodies of a 5-year-old boy and 1-year-old girl on the first floor. Two women and two men were found dead in a stairwell and the body of the shooter was found upstairs, police said.

“It was horrific. It was the worst scene I have ever experienced,” Erie Police Chief Rick Lorah said at a press conference.

An outpouring of grief and support was seen at a candlelight vigil in front of the home Saturday night as community members lit candles, left balloons, and placed stuffed animals at the active scene.

“My son heard the first shot go off and then we heard the screaming, and then we heard the next three that went off as well. So it was quite frightening for us to experience,” neighbor Candice Delange said at the growing memorial, according to WTAE-TV.

“We were here. We heard the shots. We heard everything go down, step by step. We were here while we couldn’t run into the house and help the babies,” Lisa Simmers, a family member, reportedly asked.

“How do you go home and tell your kids like, hey, your mom, your siblings, your uncles and everybody else just got murdered by your grandpa?”

Gov. Josh Shapiro spoke at a Saturday campaign event about the mass shooting and the deadly ambush of two Philadelphia police officers.

“Today has been a dark day across this commonwealth,” the Democrat said.

With Post wires