15-year-old Jaden Pierre was killed last Thursday after he was shot in Roy Wilkins Park in Saint Albans.
Police are still looking for the shooter and investigating a motive.
Last week, hundreds of teens gathered at the park for what they thought was a massive water balloon fight, instead it turned into a violent attack followed by a single shot fired into Pierre's chest.
Police have released images of the suspected gunman.
Investigators believe the shooting may be gang-related.