HOUSTON — If the police shooting of Omar Ventura on a February night five years ago had been captured on video, it would have been chilling to watch.

An off-duty Houston police officer would have been seen coming out of a bar at closing time after a night of heavy drinking. The video would have shown the officer, Jose Coronado Jr., firing his gun while trying to break up a brawl. Mr. Ventura, who was unarmed, would have been seen falling to the ground dead and his brother, also unarmed, writhing in pain from a bullet wound.

But there was no video of that shooting or of most of the dozens of other questionable shootings of unarmed people by Houston police officers during the past decade. None of them led to the criminal prosecution of an officer or significant discipline by the department.

The police in Houston, the nation’s fourth-largest city, found themselves on the defensive after a series of articles by The Houston Chronicle two years ago detailed a pattern of questionable shootings. The numbers have remained grim, according to police and court records obtained through an open records law request and documents recently made available as part of lawsuits filed against the Police Department.