RICHMOND, Mo. — A deadly house fire in Richmond, Missouri, has been ruled an accident, state officials say.

Marcus Forson, his 12-year-old son, Maddox, and Forson’s girlfriend, Charley Merriman, were killed early Tuesday morning in the fire.

Investigators haven’t released information on the cause of the fire, but the Missouri Fire Marshal’s Office said it started in an enclosed porch at the back of the house.

On Friday, a spokesperson for the Missouri Department of Public Safety said the agency has determined it was accidental. Officials are expected to release more information soon.

A memorial grew outside the destroyed Richmond home after the deadly fire. Family told FOX4 they were crushed by the news.

“It’s really unreal honestly,” Charley’s son Jonathan said. “I saw her the night before, and she stopped and gave me and my brother clothes, and I told her, ‘I love you, Mom.’”

A GoFundMe page has been set up to help the family with funeral expenses. As of Friday afternoon, more than $20,000 had been raised.