An officer was shot in Las Vegas during rioting Monday night near the Circus Circus on Las Vegas Blvd. Witnesses say shortly before midnight the officer was assisting with a group of rioters who were throwing rocks and bottles at officers. A gunshot was fired from across the street and struck Metro Officer Shay Mikalonis. Metro homicide detectives found video surveillance of the suspect firing a handgun at officers as he walked down the street. Detectives tracked 20-year-old Edgar Samaniego to a motel across the street, where SWAT officers took him into custody. He was booked on one count of Attempted Murder on a Police Officer, and two counts of Unlawful Discharge of a Firearm.   Officer Mikalonis is in critical condition at the University Medical Center Trauma Unit.