A police officer shot and killed a woman who was choking her Saturday evening in the Glen Burnie area of Anne Arundel County, the county police said.

The incident occurred about 6:30 p.m. at the Cromwell station on Maryland’s light-rail system and involved a Maryland Transit Administration Police officer, the county police said.

Two people at a bus shelter called on the officer to “intervene with” the woman, the police said. The officer tried to talk with her but was attacked. She was choked and her hair was pulled, the police said.

Even with the help of others, the officer could not break free, and finally, fearing for her life, she fired one shot, the county police said. The woman was hit in the upper leg and died at a hospital.

A police statement gave no specific cause of death, but a major artery runs through the upper leg and wounds to it may be life-threatening. The officer, who has been on the force for three years, was treated for injuries described as non life-threatening.