The Coast Guard tested the tugboat captain, a barge crew member and the camp counselor for alcohol or drugs. None tested positive, the agency said.

According to Coast Guard Sector Miami, the sailboat—with five children and an adult counselor on board—sank after being hit by the barge.

Dr. Adrian Mesa, who identifies himself on social media as a mental health professional, said his daughter, who works as a camp counselor at the Miami Yacht Club, witnessed the crash. He said she told him everyone felt helpless as they watched it unfold.