HOUSTON — A woman was shot and killed by a security guard at an apartment complex in south Houston Monday afternoon, according to the Houston Police Department.

Around 4 p.m., Sybil Collins, 27, was in some sort of mental crisis and was taking out the walls of her apartment with a sledgehammer, her sister told police.

At the time, Collins was with her three children, ages 3, 5 and 7, her sister and her sister's baby.

Collins' sister ran outside with her baby to get help from the complex's security guard, police said.

The guard came to the apartment and helped rescue at least one child. Police said he tried to reason with Collins but she began attacking him with a baseball bat.

That's when the security guard fired his gun, shooting her twice, once in the stomach and once in the arm, police said.

Collins was taken to the hospital where she died. 

The security guard is being questioned by police. It's unclear if he will be facing any charges. 

No other injuries were reported.

The apartment complex is located in the 11900 block of Martin Luther King Boulevard.

This is a developing story. Check back for updates.