Colonel Riggs was shot and killed by a Puerto Rican nationalist following a pursuit of suspect he had observed shooting at another police officer in San Juan. Colonel Riggs pursued the suspect and was able to take him into custody. As he did so a second suspect approached and shot Colonel Riggs in the head, killing him.
Both suspects were apprehended and taken to the police headquarters, where they were both killed in a reported escape attempt.
Colonel Riggs was a U.S. Army veteran who had been appointed to the Puerto Rico Police Department.