The mother of the 19-year-old accused of gunning down 17 people at Marjory Stoneman Douglas High school last month was scared of her son and contemplated signing over her parental rights to Nikolas Cruz, according to a family friend.

An unidentified source who knew Lynda Cruz and her adopted sons Nikolas, 19, and Zachary, 18, said in an interview with Fox News that Lynda had struggled with Nikolas’s disciplinary problems in the last years of her life and considered relinquishing her parental rights. Lynda and her husband Roger Cruz adopted Nikolas and Zachary when they were infants, and her husband died a few years later.

The source told Fox News that Nikolas was prone to violent outbursts, and that he once allegedly threatened her while holding an air gun while dressed in a military uniform.

Lynda reportedly told the source that Nikolas said, “Drop to your knees b—-, I’m going to blow your f—ing brains out,” before laughing and apologizing.

It is not known who, if anyone, Lynda had considered giving parental rights to her son.

“I don’t think she would have done it, she loved the boys more than anything in the world,” the source said. “She was just fed up with not getting anywhere, tired of how she was being treated and she was saying, ‘Why am I doing this to myself?’”

The source said that Lynda told her over the phone, “He thinks he’s f***ing ISIS.”

“The past few months [before she died] she was scared,” the source told Fox News. “I think that’s what killed her.”

Nikolas Cruz briefly went to live with former neighbor and family friend Rocxanne Deschamps after his mother’s death, but the arrangement was short-lived, as he and Deschamps clashed over the guns Nikolas owned.

He went to live with Kimberly and James Snead, parents of a friend, who gave him permission to keeps his weapons in the home in a locked safe. James Snead said in an interview following that mass shooting that he believed he was only one with a key to the safe, but concluded that Nikolas must have surreptitiously kept one for himself.

The source’s new revelations come shortly after a report showing that an FBI official admitted that agency staff did not follow up on two related tips connected to Nikolas Cruz — one just a month before the Valentine’s Day massacre.

The family friend told Fox News that Cruz’s overwhelmed mother, too, likely did not take all the warning signs seriously enough.

“She wrote things off that should have been addressed sooner,” the source said.

This week, Cruz was indicted on 17 counts of murder and 17 counts of attempted murder.

[Feature image: Nikolas and Zachary Cruz as children/Facebook]