BRADENTON, Fla. (WFLA) — A Bradenton man was sentenced to life in prison for murdering his 8-month-old son and the mother of his child in 2017, according to Twelfth Circuit State Attorney Ed Brodsky.

The state attorney’s office said Larry Bernard Williams was convicted this week after a jury trial for the murders of Jeremiah Shelman and his mother, Diamond Shelman, on Aug. 27, 2017.

Authorities said Williams and Diamond Shelman had the baby together but were not a couple. Instead, Williams was breaking up with his actual girlfriend, with whom he also had a baby, because of his connection to the then-18-year-old mother.

Five days before the murders, Williams told his girlfriend via text message that she won’t have to hear about Diamond Shelman or her baby again.

“During these text messages, the Defendant tells her to ‘make sure her tazor is charged real good’ and when the woman seems confused as to why he says, ‘sick of a bitch trying me now it’s on.'” the state attorney’s office said in a release. “He also tells her to ‘Look for that gas can to [sic].’ At the time, the woman had no reason to believe these text messages were anything other than a rant or that they foretold what he would do in 5 days.”

Officials said in the early morning of Aug. 27, 2017, Wiliams went to Diamond Shelman’s apartment, stabbed her to death, spread gasoline in the unit, and lit it on fire. The 8-month-old was also killed in the fire after inhaling too much smoke.

“Diamond was 18-years-old and had her whole life ahead of her,” Assistant State Attorney Suzanne O’Donnell said. “Jeremiah’s life had not yet even begun. These crimes are about as tragic and senseless as they come.”

When questioned by investigators, Williams said a demon killed his son and his mother. However, another man who was detained in the Manatee County Jail testified that Williams admitted to the murders days after his arrest.

“He also said he told the police that ‘demons did it’ and asked the witness if he thought they would buy the excuse and if it would work,” the state attorney’s office said.

Williams’ defense tried to play the insanity card by having two doctors testify his insanity, but once they learned of the text messages and the jail witness’ statement, they refused to support the defense.

“This case was extremely difficult for everyone involved from the first responding firefighters, to the Manatee County Sheriff’s homicide detectives, to the Fire Investigators. But everyone stayed the course to see that justice was done,” O’Donnell said. “I, and the State Attorney’s Office, and especially the victim’s family with be eternally grateful. And we are grateful to the jury that endured hearing the facts of this case yet stayed focused to ensure that justice was done.”

Williams was given two consecutive life sentences for the murder charges. He will have a later trial date for the arson charge.