A video showing a Philadelphia police lieutenant unexpectedly punching a woman in the face represents yet another damaging blow to the Police Department's already tarnished reputation.

The images of a decorated cop, Lt. Jonathan Josey, walking up behind a bystander at the Puerto Rican Day celebration Sunday - and then striking her to the ground with two bloodying blows - are shocking and, as a police officers' group described the scene, "deplorable."

It's conceivable that a police Internal Affairs investigation into the incident ordered Monday by Police Commissioner Charles H. Ramsey will reveal details that prove Josey's actions were within bounds. But there's certainly no hint of that in the video. Aida Guzman, appears to pose no threat. Nothing in the video suggests she did anything to warrant being pummeled before being arrested on a disorderly conduct charge for allegedly throwing water on police.

So Ramsey needs to make sure the in-house probe is conducted thoroughly and swiftly, with the full results immediately disclosed to the public. The commissioner also needs to offer greater assurances that he has a workable strategy to require higher standards of conduct, especially in the department's upper ranks.

In addition to Josey, who runs a violence-prevention program in his spare time and has been honored for crime-fighting heroics, several police commanders recently have been accused of misconduct. But a full accounting for Josey's troubling YouTube moment must be a priority for Ramsey.