The incident happened Friday when officers responding to a domestic violence incident led to an alleged altercation between police officers.
Colwyn Police officer Clinton Kraddock was driving through neighboring Darby Borough when he was flagged down.
Kraddock called Darby Borough for back-up as he was taking a man into custody. Among the responding officers was Darby Borough Police Chief Robert Smythe.
Action News has learned there were heated words between the two, ending when Smythe allegedly slammed a car door on the officer's leg.
"What I have always contended and still have the contention of is for all of us put into what was created in that mutual aid agreement, which is everyone back each other up," said Kraddock.
Action New reached out to Chief Smythe, but he had no comment.
Lt Wendell Reed of the Colwyn Police Department and Colwyn Council President Tonnette Pray spoke of a history of tension between the departments when it comes to Darby police officers backing up Colwyn. They had hoped it was resolved.
"This is something that's very, very upsetting to me," said Tonnette Pray.
"There was an altercation that occurred, everything is, I won't say sketchy, but it is being handled by CID, so I can't really get into the specifics at this time," said Lt Wendell Reed of the Colwyn Police Department.
Mayor Helen Thomas of Darby Borough would only say she's aware of the situation and trying to get to the bottom of it.