The gunman who slaughtered two children and injured 18 other people at a Minneapolis Catholic school and church had recently broken up with his romantic partner — and previously had a “medical mental health” call made to his home when he was a teen, according to police records.

The father of Robin Westman, 23, told investigators that the shooter had “broke up with a significant and/or romantic partner” and had been staying with a friend, Fox9 reported.

Police were also made aware of a 2018 welfare check at the home of Westman’s mother, with the incident involving a juvenile, according to police records.

Westman died from a self-inflicted gunshot after the shooting and identified as a trans woman, but claimed to have “brainwashed” himself into being transgender.

Westman opened fire through the stained glass of Annunciation Church in Minneapolis on Wednesday just after 8 a.m., firing at the children and parishioners sitting in the pews during mass celebrating the first week of school.

Just hours before the massacre, Westman posted a series of twisted videos on YouTube, which included a manifesto, Minneapolis Police Chief Brian O’Hara told reporters.

In the deranged writings, he gleefully fantasizes about “being that scary horrible monster standing over those powerless kids” and reverently confesses admiration for the 2012 Sandy Hook massacre.

Westman also sent a deranged goodbye letter to his family and friends where he claimed to embody “traits of empathy, self-sacrifice, and good character” and to be raised “to be a good person” — while also declaring he “wanted” to slaughter innocent children while also asking for prayers for his victims.