Five people were found dead in apparent murder-suicide shootings Sunday at homes in two well-to-do suburbs of Washington, police said.

Officers found the bodies of three men and one woman in a house in Great Falls when they responded to reports of gunfire at about 10:25 a.m., Fairfax County Police said.

Police said they believe one of those found dead at the first house was responsible for all the shootings.

They treated the first shooting scene as a barricade situation until they determined that the gunman was dead after a 20-year-old man came out of the house.

An investigation at the first crime scene led officers to another house in the Tyson's Corner area, about a dozen miles west of downtown Washington, where they found the body of a woman.

Police said the same person appeared to have responsible for all the deaths, but gave no further details.

The Washington Post, citing unnamed police sources, said a man shot his mother at one of the houses before driving to the other location and shooting the others and taking his own life. His relationship with the people at the second house was unclear.

None of the people involved were identified immediately by police.

"We do believe that the suspect in this case knew the people that he actually killed," Fairfax County Police Officer Rich Henry said. "That he was not a stranger."

One of two dogs at the house where the four bodies were found had been shot several times.