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

Pike County Coroner Jason Jones told The Associated Press that the slain suspect was Branen Carter, 21.

Carter was at the Social Security Administration office in McComb with his mother, Lee Anna Turnage, and grandmother, Ann Carter. Jones said another relative told him Turnage and Ann Carter had an appointment there and gave Branen Carter a ride. The family came from Foxworth, about 40 miles (64 kilometers) east of McComb.

The Enterprise-Journal reported that two witnesses said there was an argument between Branen Carter and Turnage before the stabbings.

Large numbers of law enforcement officers converged on the one-story brick building on the edge of McComb, about 100 miles (160 kilometers) south of Jackson.

Ann Carter, 58, was in critical condition at Southwest Mississippi Medical Center in McComb hours after the stabbing, hospital spokeswoman Tina Brumfield said.

Brumfield said Turnage was taken by helicopter to the University of Mississippi Medical Center in Jackson. A UMMC spokesman, Marc Rolph, said nobody named Turnage was on the public registry of patients. A person's name can be withheld from a patient registry for multiple reasons, including a request by relatives or law enforcement officials.

Mississippi court records show Branen Carter was indicted in Marion County in December 2016, when he was 20, on two felony charges — one count of statutory rape and one count of sexual battery of a child between the ages of 14 and 16.

He pleaded guilty in May 2017 after the two felony charges were reduced to misdemeanors, and he was given two six-month suspended sentences, which means he did not have to serve jail time. The attorney who represented him was out of the office Monday and could not immediately be reached for comment.