Seven people were shot and killed at a home in a Dallas suburb where they had reportedly gathered to watch a football game, authorities and neighbors say. A police officer who arrived on the scene exchanged gunfire with the suspected shooter, who was killed.Two other people were wounded in the incident, police said. There was no immediate word on their conditions.The shooting occurred around 8 p.m. local time Sunday in Plano, about 20 miles northeast of Dallas. The victims, who were all said to be adults, had held an afternoon barbecue ahead of the Dallas Cowboys-New York Giants game, according to neighbors.A nearby officer heard gunfire and responded, The Dallas Morning News reports.The officer "made entry, and that's when he observed several victims inside and then engaged the suspect," police spokesman David Tilley was quoted as saying by the Morning News."We're looking into a motive," Tilley said, adding that the relationship between the victims and the shooter was unknown as yet. However, the newspaper writes that: