On the night of July 30, 2016, around midnight in a parking lot near 18th and Market Streets in Denver’s LoDo district, 20-year-old Gailen Armstrong was killed in a massive shootout. Investigators say the violence involved rival gang members, with more than 200 rounds fired from at least 18 different weapons. Another man was injured; Gailen was pronounced dead at the scene from gunshot wounds and no arrests or suspect descriptions were released at the time.

Known to his family as Gator, Gailen was a father to a four-month-old son and according to his girlfriend and relatives had recently found a job and was trying to turn his life around. Reports also say the city’s gang unit had been warned about possible violence in LoDo that night but officers were sent home early, a decision later described by a deputy chief as a mistake.

The case remains unsolved and is listed among Colorado’s cold cases. Anyone with information about the July 30, 2016 shooting is asked to contact the Denver Police Department.