KWTX-TV, Waco, reported the state Department of Public Safety identified the gunman as Jose Antonio Lopez, 29, of Georgetown.
Williamson County sheriff's spokesman John Foster told the Austin American Statesman deputies were called to a home in Georgetown around 10 p.m. Sunday and found the three victims, who were not identified.
Officer's got a description of the gunman's pickup and spotted it traveling south on Interstate 35. State troopers tried to pull him over, but he rammed into an empty Round Rock police patrol car and died, Foster said.
Lopez was pronounced dead at the scene just after 11:45 p.m.
Foster said the wife was staying with her parents because she was getting a divorce. Three other people, including a 1-year-old child, got out of the home unharmed.