An East Cooper family left homeless after their house was apparently firebombed wants to know why it happened.

A teenager was arrested Thursday after a neighbor said she saw him tossing a burning device the day before inside the house at 2769 Rifle Range Road. Raheim Bradley, 18, of Boston Grill Road, is charged with third-degree arson.

Julie Williams, a preschool teacher, lived in the house with her husband and two sons, 18 and 23. She said she didn’t know Bradley but figured her sons did.

“I’m just so confused as to why he felt he had to do this,” she said. “He still has a roof over his head and we don’t. I just don’t know why.”

The family was not in the house when the fire started.

“Nobody was there, thank God,” she said. “It’s completely destroyed.”

The Red Cross lined up a motel room for three nights and gave them money to replace some of the losses.

“We’re on our own after Saturday morning,” Williams said. “At this point, it’s pretty overwhelming.”

The single-story cinderblock house is between Hamlin and Porchers Bluff roads. A crew from the Awendaw Fire Department arrived at 4:45 p.m. Wednesday and saw flames inside and smoke pouring out from under the roof, according to Chief Tommy Norris. The blaze gutted the interior, he said.

Fire investigators confirmed that the fire appeared to have started just inside the entrance of the house. They were looking into what was used to start to the fire, and deputies were trying to determine the motive for the attack, sheriff’s Maj. Jim Brady said Thursday night.

A neighbor told deputies she saw a young man wearing dark clothes and a hoodie toss something through the front door of the house just before the fire broke out, according to the incident report from the Charleston County Sheriff’s Office.

She said she saw something flash inside the house and smoke start pouring out, then saw the young man run off toward Jefferson and Boston Grill roads.

Another neighbor said the young man was named “Raheem” and lived on Boston Grill Road.

Bradley had never been arrested before, according to a background check with the State Law Enforcement Division.

Third-degree arson involves property damage but no injury to people and is punishable by up to 15 years in prison.

Bradley also was charged with first-degree burglary. A bond hearing is expected at 9 a.m. today.

Reach Dave Munday at 937-5553 or twitter.com/dmunday.