Boaters leaving celebratory Fourth of July fireworks off the coast of Miami collided, killing four people and injuring a dozen others, according to police.

The pyrotechnic show ended Friday night, and as boats were returning to marinas near Biscayne Bay around 10:45 p.m., several boats crashed into one another.

"One vessel crashed into another, then that vessel hit a third," Florida Fish and Wildlife Conservation Commission Officer Jorge Pino said Saturday. "It's possible that these boats were rushing to get back to the boat ramp to get out of the water."

Pino said as many as five people were thrown from the boats and up to 12 were taken to local hospitals. Two victims died at the hospital Friday night, and two additional victims were found dead in the water Saturday morning. One person hospitalized is listed in critical condition, according to Pino.

The three vessels involved in the crash were one larger boat and two "open-fisherman-style" boats. According to Pino, the accident was actually two separate collisions, one right after the other, but it is unclear what caused the initial crash. All of the boats were towed back to shore and will be held for investigation.

The Coast Guard in Miami said it responded to a report from a boater on a 36-foot vessel after another boat had struck it. The call said that passengers had fallen overboard and that the other boat did not stop following the crash. When the Coast Guard attempted to contact the owner of the boat that supposedly struck the boat, the owner reported that his son had taken the vessel out Friday.

Miami-Dade County had 104 boating accidents in 2013, the highest of any county in Florida, according to the Fish and Wildlife Conservation Commission.

Pino added that neither he nor fellow officers could remember a deadlier crash.

"The most that I can remember is three people died in Collier County about three years ago," he said. "But as far as four fatalities in one single accident, I've never heard of that."