PALM VALLEY, Fla. -- One day after 22-foot Crownline boat crashed into a 25-foot tugboat in the Intracoastal Waterway, investigators said they've removed the boat from the area and will process it as a crime scene.

Five people died and at nine others were seriously hurt when the pleasure boat packed with 14 people slammed into the tugboat tied up to a dock under construction on Easter Sunday evening.

The Florida Fish and Wildlife Conservation Commission said a boat struck the tug docked along South Roscoe Road -- about one mile north of the Palm Valley Bridge.

"It had to be doing at least 30 to make that kind of noise and to go through the boat like that," said George Hume, who called 911 after hearing the crash and people screaming. "That boat went three or four feet into the other boat, so you know that that impact -- when it hit, those people just went forward. And, of course, those people were hitting steel."

St. Johns County fire-rescue personnel said the power boat penetrated the hull of the tug, as well as the wheelhouse and the engine compartment.

Rescuers used plywood pulled from the construction site to build a bridge to reach those in the water and wreckage.

"They took them to the barge and did a triage there to determine which patients were going to make it off the barge and across the improvised dock ... to be able to get them up to a treatment area," Chief Carl Shank of St. Johns County Fire-Rescue said.

Five people were pronounced dead at the scene and at least seven others were transported to Jacksonville hospitals.

By midday Monday, two of those at Shands-Jacksonville Medical Center remained in critical condition, one in serious condition and three in fair condition.

One of those hospitalized was the boat's owner, Melvin Bethel, according to FWC Lt. Steve Zukowsky.

"The boat has been removed from the water and is being processed now as a possible crime scene," Zukowsky said. "We're looking at things to see if there was possibly foul play. We have to rule that in or rule that out."

The FWC, which was leading the investigation, had questioned several witnesses and was seeking others. The Coast Guard and National Transportation Safety Board have also joined the investigation to try to find out exactly what happened in the moments before the crash.

Among the questions investigators were asking were why 14 people were on a 22-foot boat, how fast were they going, were the passengers wearing life vests and whether alcohol was involved.

Authorities said it would take weeks to complete the investigation.

Alan Oshier, of Neptune Beach, told Channel 4 that he had overslept or he would have been on board the boat, which left St. Augustine Beach's Conch House after the group had spent the afternoon of listening to music. The FWC believes the boat was headed back to Beach Marine at Jacksonville Beach when it hit the tug.

St. Johns County Fire-Rescue spokesman Jeremy Robshaw described the rescue scene as chaotic, with firefighters, deputies and other agencies all trying to rescue victims.

"You see tragedies occur from time to time, but this is a pretty significant thing," Robshaw told Channel 4.