Leominster authorities launched an internal investigation into whether one of the city's police officers is the heckler responsible for shouting a racial slur at Red Sox left fielder Carl Crawford during a minor league game last week in Manchester, N.H.

"The officer will be assigned to desk duty until our investigation is done," said Leominster Mayor Dean Mazzarella.

The investigation is expected to be completed within the next several days and the officer, who Mazzarella did not identify, has been away from the department on vacation since the July 5 game.