An 18-year-old Oklahoma man already under investigation for the rape of a 14-year-old girl was arrested and charged last month with plotting the murders of a different ex-girlfriend and her mother.

Matthew Austin reportedly told a witness he was angry with the ex-girlfriend, who he claimed was “messing with his life” by refusing to drop a separate rape case against him, KWTV reported.

The witness reportedly advised the teen not to try such a cockamamie plan, but he insisted it was fool-proof and that he planned to “just stab them so that they would not scream.” The witness called police after he left, and officers found him near the ex-girlfriend’s home with a Home Depot bag that contained a painter’s mask and latex gloves.

“I think he initially provided officers with an excuse like he was going to paint his room or something along those lines,” said Norman Police spokesperson Sarah Schettler.

Austin was arrested on July 18, according to Law&Crime, and eventually admitted his plans to kill his ex and her mother. He also told them he was under investigation in Moore for the alleged rape of the 14-year-old girl, telling them he believed her to be 19. He was ultmately charged with rape on August 1.

A warrant for his arrest said that that the Moore investigation began on July 14 when the girl’s mother contacted police about the alleged rape. She showed officers text messages between Austin and the girl, beginning when they first met through church. Police said Austin told the girl he was 16.

During a forensic interview, the victim said Austin “visited her residence and forced himself on her and raped her,” the affidavit said. telling her “everything would be fine and not to tell anyone due to their age and it needed to be a secret.”

He also told the victim “that he had done this before and told her it was going to be OK,” the affidavit said.

Bond on the rape charge is set at $400,000. In Norman, he is charged with planning an act of violence, with bond set at $25,000, and devising a plan to cause serious bodily harm and intimidating witnesses, with bond set at $5,000 each on those charges.

He’s also been charged with possession of a controlled substance and is being held in the Cleveland County Jail.

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[Featured image: Matthew Austin/Cleveland County Sheriff’s Office]