Three people, including a 13-year-old girl, were shot dead at an Arkansas home on Saturday, with four others injured, the Associated Press reported.

After killing a teenager and critically wounding two boys, the suspected gunman was found dead in his vehicle, police said. He was an acquaintance or friend of the victims, police said Sunday, but noted the motive still is unknown.

Police in Jonesboro, in Craighead County about 130 miles northeast of Little Rock, said they received a call early Saturday afternoon reporting a shooting at a residence, Reuters reported.

Around 1:00 p.m., police received a 911 call about the shooting at the home. They responded at 1:22 p.m. to a report of a second shooting at a business near a U.S. highway.

The suspected gunman was later found dead of a gunshot wound in the driver's seat of a stopped car, Jonesboro police Sgt. Doug Formon said at an evening news conference. It was not immediately clear if the gunshot was self-inflicted.

According to Reuters, two boys, aged 10 and eight, were listed in critical condition at a Memphis, Tennessee hospital, and two other adults, one man and one woman, were also shot, Jonesboro Sgt. Doug Formon told a news conference.

Another man was later found shot and killed at a nearby place of business where he worked, a site where construction and lawn work had been ongoing, Formon said. Identities of the victims have not been provided.

"The presumed gunman was found in the driver's seat of a vehicle on a highway, dead of a gunshot wound, and the investigation was continuing, Formon said. Witnesses reported seeing the vehicle leaving the scene of one of the shootings," Reuters reported.

"Formon said police were still trying to determine the motive of the shootings and were investigating 'to see if there were any more suspects involved,' but that the man found dead in his car was thought to be the only suspect."