DALLAS (TIP): Police were trying to determine Thursday, August 8 what prompted fatal shootings in two Dallas-area homes that left four dead and another four wounded. Investigators arrested a suspect, Erbie Bowser, 44, at the scene of the second shooting, which took place late Wednesday. Police say the shootings began around 10:30 p.m. Wednesday at a Dallas home, where two people were killed and two others were injured, according to the Dallas Morning News.

Two more people were killed and two children were wounded at a second home in DeSoto, where police said a hand grenade was thrown into the living room before the shooting began, the Morning News reported. Police did not immediately release the identities of those killed and wounded, and the conditions of the survivors were not known Thursday. A neighbor in DeSoto, Tommy Johnson said that he heard a loud boom Wednesday night. “I peeped out the front, and that’s when I saw a bunch of officers walking down the sidewalk and about 10 houses up,” Johnson said. Police would not confirm that a grenade or other explosive device had been used in the DeSoto attack, pending the results of a federal and Dallas bomb squad investigation.