As investigators pieced together one of the deadliest recreational boating accidents they’ve ever seen in South Florida, on Monday they added alcohol to the list of possible factors contributing to a crash that killed four people and injured eight more.

“After doing a thorough inventory of the vessel, we did discover evidence of alcohol on board”the Contender that was involved in the accident, Florida Fish and Wildlife Conservation Commission spokesman Jorge Pino told the Miami Herald.

He stressed that it was too early to draw any conclusions because toxicology tests on the victims are still pending.

Pino confirmed Monday that the Contender was piloted by 23-year-old Andrew Garcia, the son of a retired Miami-Dade fireboat captain who was critical of the region’s sidelining of fireboat rescue vessels.

Garcia was knocked overboard and killed in the initial collision. Two passengers, Victoria Dempsey, 20, and Kelsie Karpiak, 24, also died. Two others aboard, Catherine Payan, 24, and Samantha Rolth, were critically injured.

Pino said the Contender struck a Carrera, where passenger Jason Soleimani, 23, died on impact. Another passenger, Dayanara Arias, 39, was critically injured and remains hospitalized. Her two young daughters escaped unscathed. Other members of the Hanono family aboard the Carrera had less-serious injuries.

Eight people on the third boat, a 35-foot Boston Whaler center console, were not seriously hurt.

Pino said investigators are examining GPS navigation units, lights and other instruments on all three boats, which are impounded at the FWC facility in North Miami, to “put the pieces of the puzzle together.”

“We are downloading GPS information and taking all the physical evidence we have and documenting it,” Pino told the Miami Herald.

No charges have been filed in the accident, which happened about 10:45 p.m. Friday about 1-1/2miles southeast of Dinner Key in Coconut Grove. The crash followed the conclusion of an Independence Day fireworks display, which typically precedes a scramble as many boaters rush in different directions to various marinas.

Kevin Karpiak, who was on the Contender when his sister was killed that night, said Garcia was an experienced, safe skipper.

“He was a good fisherman. A good boat guy. He always took responsibility,”Karpiak said.