City Councilman Michael McMahon, after a briefing from city emergency and transportation officials, said the crash may have been related to the pilot's health and medication he was taking for a possible blood-pressure problem.
The pilot, Assistant Captain Richard Smith, attempted suicide after the crash by slitting his wrists and shooting himself with a pellet gun, police said.
"The assistant captain at the controls collapsed," McMahon said. "By the time the other captain could get control of the ship, it was too late."
Although the focus is on Smith, sources tell CBS News the man actually in charge of the boat, Captain Michael Gansas, was not in the vessel's pilot house at the time of the collision. Captain Gansas denies the story.
New York City transportation officials say if it's true, Gansas broke protocol.
"Traditionally when a boat is approaching one of the terminals, the captain and the assistant captain are in the pilot house together," said Iris Weinshall with the NYC Dept. of Transportation.
The 310-foot ferry slammed into a concrete pier as it approached the Staten Island shore in choppy, wind-swept waters Wednesday afternoon, ripping a giant hole along its right side and severing the limbs of three passengers. Some passengers leaped into the water.
The crash left more than 60 people hospitalized, eight in critical condition. The dead, one woman and nine men, ranged in age from 25 to 52. For many families on Staten Island, the realization of the loss hasn't set in.
CBS News Correspondent Jim Acosta spoke with Osserritte Robinson, whose husband of just 8 months, Louis, died in the crash.
"I'm praying it's a mistake. But in the back of my head, I know it's not," Robinson said.
There was one bit of good news: A missing woman, presumed to have died in the water, turned up safe at a friend's house, police said.
The fractured ferry sat at the docks Thursday as thousands of commuters boarded boats for the morning rush hour.
"If you look at any photograph of a terrorist attack on a bus or train in the Middle East, that's your idea of what it looks like," Staten Island Borough President James Molinaro said.
Witnesses said the vessel appeared to speed up as it approached the shore. A source close to the probe, speaking on condition of anonymity, said the captain told investigators that Smith "slumped forward" on the controls in a way that could have made the boat accelerate toward the pier.
Blood samples were taken from Smith and the rest of the crew. Early test results on Smith indicated alcohol was not a factor, according to a high-ranking law enforcement, source speaking on condition of anonymity. Authorities were still investigating whether prescription drugs played a role, the source said.
Alan Abramson, an attorney for Smith, issued a statement that said only: "The family and all concerned hope that people will not rush to judgment. Their prayers go out to all the victims."
Smith, 55, was a 15-year ferry veteran whose record gave no indication of a blood-pressure problem, said City Transportation Commissioner Iris Weinshall. Smith remained hospitalized in critical condition.
Smith was also at the helm of the same ferry when it crashed into a Staten Island dock in July 1995, investigators said Thursday. The accident, which led to several injuries but no deaths, was blamed on a propeller failure.
The investigation, led by the National Transportation Safety Board, was also looking into whether the pilot and captain both should have both been in the pilot house as the vessel approached the dock. Under city Transportation Department procedures, that typically happens, although it is not a Coast Guard requirement.
"If the policy of the Department of Transportation was implemented at the time of the accident, we don't know," said NTSB chairwoman Ellen Engleman
McMahon expressed skepticism that anyone had been close to Smith: "It's hard to believe that someone who was right there could not gain control of the ship."
Smith spoke with police on Wednesday, but had not yet been interviewed in depth, Engleman said. The NTSB was already speaking with members of the crew, ferry engineers and some of the victims, she said.
Investigators were also speaking with an attorney for the ship's captain to arrange a session with him.
Engleman said her agency had "a lot of conflicting reports" about the pilot's condition before the crash. "We don't want to pass on stories or rumors," she said.
Engleman added that the NTSB investigation would consider other possible causes, such as the weather and engineering factors.
Ferry service resumed Thursday morning, with Molinaro reporting that the number of riders did not appear down. The ferries, with their free, 25-minute cruise across New York Harbor, ordinarily carry 70,000 people daily between Staten Island and lower Manhattan.
The mangled front right side of the ferry was shored up to prevent a collapse of its upper deck. Several of the victims were dug out by rescue workers from beneath a pile of broken glass, shattered wood and steel.