Agents with the federal Bureau of Alcohol, Tobacco, Firearms and Explosives served a search warrant Thursday at the home of a Pasadena Police Department officer who has been placed on paid administrative leave pending an internal affairs review.
The officer, who cooperated with ATF investigators, has not been arrested or charged, according to city of Pasadena spokesman William Boyer.
Boyer did not confirm the nature of the investigation.
A representative from the ATF Los Angeles field division told NBC4 the investigation was ongoing and said ATF currently has "no comment."
The officer was placed on leave, per department policy, by Pasadena Police Department Chief Phillip Sanchez, "who does take this very seriously," Boyer said.
Officials with the ATF informed Sanchez of the investigation on Wednesday night and told the chief it is not related to the officer's work in the department, Boyer said.
Boyer said he did not know what, if anything, was taken by the agents from the officer's home.
A Pasadena Police Department spokesman did not immediately return NBC4's requests seeking comment.
Ryan Bourgard and Robert Kovacik contributed to this report.