A Mississippi man stabbed his mother and grandmother in a federal government office and was then shot to death by a security guard.

Pike County Coroner Jason Jones tells The Associated Press that 21-year-old Branen Carter died of the gunshot wound today.

Carter was at the Social Security Administration office in McComb with his mother and grandmother. Jones says another relative told him the mother and grandmother had an appointment there and gave Carter a ride. The family came from Foxworth, about 40 miles east of McComb in Marion County.

The mother and grandmother were hospitalized, and information about their conditions was not immediately available.

Large numbers of law enforcement officers responded to the one-story brick building on the edge of McComb, about 100 miles south of Jackson.