A deranged Arizona teen allegedly shot his 16-year-old pregnant girlfriend dead after repeatedly threatening her life when she found out she was expecting his baby, according to her devastated family.

Michael Sanchez, 18, was thrown behind bars after opening fire on his girlfriend, Rylee Montgomery, and her two friends – including a 17-year-old girl who was also pregnant – outside a Buckeye home around 8:15 p.m. Thursday, the Buckeye Police Department said.

Montgomery and her unborn baby died at the scene.

Her expecting pal and a 22-year-old woman were rushed to a local hospital in critical condition, cops said.

“Our sweet girl fell victim to a controlling boy,” Montgomery’s stepmother, Amy, wrote on a GoFundMe, alleging Sanchez turned violent in February after the slain teen got pregnant and refused his chilling demands to “kill the baby.”

“He started off very sweet and nice to her. Once he got her pregnant in February, it was all over. After telling her to ‘kill the baby,’ and when she refused, he turned his anger on her, threatening her numerous times. He even went so far to choke her at our house.”

The grieving stepmom said Montgomery broke up with Sanchez in March – only for him to allegedly point a gun at her face and tell her that wasn’t allowed. He then sent disturbing photos of himself with a gun to his head alongside a text, “I’m going to get you.”

The frightened teen reported the incident to police, but authorities allegedly said there wasn’t enough evidence to file charges, Amy told AZ Family.

“It’s like somebody ripped my freaking heart out,” she told the outlet.

“She was so scared of him, and we tried to get her help.”

The horrifying triple shooting left one of Montgomery’s friends shot at least three times and the pregnant victim struck in the back – nearly bleeding out before being forced to deliver her baby boy prematurely at just 25 weeks, according to the fundraiser.

Police said Sanchez fled the deadly scene and was later tracked to a home in Avondale, about 18 miles away, where he was cuffed and booked on multiple charges, including two counts of first-degree murder.

The unhinged boyfriend was reportedly wearing an ankle monitor on the night of the deadly shooting.

Sanchez was placed on felony probation and ordered to wear the monitoring device in March in connection with a DUI, court records obtained by AZ Family show.

He is reportedly due back in court next week.