MCCOMB, Miss. — 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 told The Associated Press that 21-year-old Branen Carter died of the gunshot wound Monday.

Pike County Sheriff Kenny Cotton told The Enterprise-Journal of McComb that the attacker entered a Social Security Administration office in the southwest Mississippi city Monday morning and stabbed two people.

Carter was at the Social Security Administration office in McComb with his mother and grandmother. Jones said 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.

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.