ATLANTA -- A civil rights activist representing the family of an elderly woman killed in a gunfight with police will ask for a federal investigation into her death.

The Reverend Markel Hutchins says he will travel to Washington on Monday to deliver a letter to Attorney General Alberto Gonzales requesting a Department of Justice and FBI investigation into the death of Kathryn Johnston.

Johnston, who police said was 92, was killed Tuesday evening by undercover narcotics agents. Authorities say the agents had obtained a search warrant for Johnston's home after buying drugs that afternoon from a man there. Police said the agents identified themselves, but when they knocked down Johnston's door, she opened fire and injured three of the officers.

Hutchins said he has spoken with U.S. Representatives John Lewis and Cynthia McKinney about the incident.

Neighbors and relatives have called the incident a case of mistaken identity.

Fulton County District Attorney Paul Howard said his office has launched its own independent investigation into the fatal shooting, but said a preliminary review of the case shows the offiers "had a legal right" to search the home.

Bullets struck one officer in the arm and another in the leg. The third officer was hit three times -- in his leg, on the side of his face and in his bulletproof vest. Authorities said all of the officers are expected to recover.