LUTTRELL, Tenn. (WATE) — A months-long investigation has determined a Union County man shot four children and set his house on fire before committing suicide, the district attorney wrote Monday.

Eighth Judicial District Attorney General Jared Effler filed a memorandum on Monday following an investigation into a January 29 house fire in Luttrell. He made the determination that Charles Aljumaily shot four children and killed himself based on evidence found by Tennessee Bureau of Investigation special agents.

Briseis Aljumaily, 15, Audrie Cooper-Fortner, 9, Gabriella Aljumaily, 5, and Evie Cooper-Fortner, 5, were found dead in the home.

Effler wrote that autopsies and ballistic evidence indicate that all four children were shot before the house caught fire. Charles Aljumaily, the father of Briseis Aljumaily and Gabriella Aljumaily and grandfather to Audrie and Evie Cooper-Fortner, is believed to have shot all four before setting the house fire and shooting himself.

Autopsies determined that all four were killed by gunshots from a .45 caliber Sig Sauer handgun, which was found near Charles Aljumaily. He died from a single gunshot to the head. The gun was purchased by Aljumaily in 2013 and registered to him.

Special agents found that the deadbolt on the home’s front door remained in a locked position after it had been breached by firefighters.

TBI special agents interviewed multiple family members. One told an investigator that Aljumaily was diagnosed with borderline bipolar disorder. They reported he had been paranoid recently and told them for the last few months that there was “a devil in his head attacking him.” He also reportedly said he wanted to harm himself but was afraid to because of how that would affect his salvation.

A relative also told a TBI agent that they suspected Aljumaily of being bipolar and that he was on medication, but stopped taking it because he did not like how it made him feel.

Another relative told investigators that Aljumaily said a few months prior that he “felt like ending it.” Minutes before the fire was reported, Aljumaily told a relative by phone that “it’s bad right now, it’s not good right now.”

Effler wrote that no criminal charges will be brought because Charles Aljumaily is dead.

“In my twenty-three(23) years as a prosecutor, this is one of the most tragic and heartbreaking cases I have ever encountered,” wrote Effler about the case.