To the police officer who was there, what happened Halloween night inside a Houston jail certainly qualified as a crime: An inmate locked up on suspicion of drunken driving tried to pull another inmate toward him while exposing himself.

The other inmate screamed for help. An officer approached and barked commands at the drunken driving suspect, according to a police report, “to get his hand off the complainant and to pull his pants up.”

The officer then reported the episode to the Harris County District Attorney’s Office, expecting the drunken driving suspect to also be charged with attempted sexual assault.

But he was not — at least not at first. An assistant district attorney, John Denholm, questioned the officer about the victim’s immigration status and whether the victim would be willing to testify.