WASHINGTON (AP) _ An alleged failure by a Bureau of Alcohol, Tobacco and Firearms agent to follow a lead on killings outside CIA headquarters is not responsible for the suspect's escape, Congress' investigative arm says.

''Our investigation disclosed that the suspect had left the country on Jan. 26, 1993, one day before the BATF agent visited the gun store'' where employees say they told him they knew the attacker's identity, the General Accounting Office said Thursday

Its report sided somewhat with the gun store employees who said they told the agent they recognized the assailant from a composite drawing he showed them.

The agent, whose name has not been released, has denied the employees told him anything of the kind.

The investigation followed up on allegations raised in a Washington Post story about the gun store where Mir Aimal Kansi bought the AK-47 he used to allegedly kill two CIA employees and wound three people at a CIA entrance in McLean, Va., on Jan. 25, 1993.

David Fischer, a gunsmith at the David Condon Inc. store in Chantilly, Va., said he told the agent he recognized the drawing as Kansi and gave the agent Kansi's name, but the agent seemed to dismiss his information. His statements were supported by the store's manager, Britton Condon. Kansi remains at large.

The agent was in the store on Jan. 27, 1993, to check records on gun sales.

''Although the evidence developed during our investigation tends to support the statements of the gunsmith and the store manager, the BATF agent involved denies that the gunsmith provided any identification of the composite,'' the GAO report said.

Patrick Hynes, special agent in charge of the ATF's Washington field office, told the GAO ''he believes the gun store employees are being untruthful'' and noted that they did not go public with their statements until after Kansi was identified as a suspect.

Hynes ''also raised the issue that the gun store owner, to protect himself from liability in the shootings, had fabricated the story about the BATF agent's ignoring the gunsmith's identification of the composite,'' the report said.

''That's silly,'' Britton Condon said in an interview Thursday. ''We have to live and work with the ATF, so there's no reason to stir up trouble with them.''