Media playback is unsupported on your device Media caption Sgt Robert Eberling: "It's the worst investigation we've had to investigate in many years"

Seven bodies with gunshot wounds have been found in a flat by police in the US state of Texas.

The victims - four women and three men - were discovered in the city of Grapevine, just outside Dallas.

Local police said they believed one person shot the other six before committing suicide, NBC 5 reports.

The ages of the victims reportedly range from late teens to sixties. Their names have not been released. A police investigation is now under way.

The victims appear to be three generations of the same family, according to NBC 5.

Handguns

The bodies were found in the flat on Sunday morning. Two handguns were also discovered inside.

"It appears to be they're all related. It appears all the victims are deceased from gunshot wounds," Grapevine police Sgt Robert Eberling was quoted as saying by the Associated Press news agency.

"We are pretty confident that the shooter is among the deceased victims inside the apartment. We are not actively looking for a shooter that we believe is at large," the police officer added.

Officials said all seven bodies were found near a Christmas tree in the living room.

"It appears they had just celebrated Christmas. They had opened their gifts," Sgt Eberling said.

He added that police rushed to the flat after receiving a 911 emergency call.

"There was an open [telephone] line. No-one was saying anything."