Long Island Police Call In F.B.I. Divers to Recover Boat Police officers on Long Island have called in a dive team from the Federal Bureau of Investigation to help them recover the boat that capsized and sank near Oyster Bay on the Fourth of July, killing three children. Steven Skrynecki, the chief of the Nassau County Police Department, said on Monday that the F.B.I. was the best-equipped agency among those the police had considered asking for help. He said a dive team from the bureau's headquarters in Quantico, Va., would use video cameras and sonar to get a picture of how the boat is lying 60 feet beneath Long Island Sound. Then, Mr. Skrynecki said, they would attempt to use "air bags" to float the boat to the surface on Tuesday and drain enough water from it so that it could be towed to shore for inspection. Nassau County homicide detectives will not be able to complete their investigation into the deadly sinking until they can see the boat, he said. So far, no charges have been filed against the owner or the driver of the boat, two brothers-in-law who led a group of relatives and friends out onto the water on the holiday to watch a fireworks display. The police say that 27 people, including 10 children, were on the boat, a 34-foot cabin cruiser designed to hold far fewer passengers. But they have not said that overcrowding caused the boat to capsize, and Mr. Skrynecki declined to say on Monday whether alcohol could have been a factor. The boat, known as the Kandi Won, flipped over just after 10 p.m. on Wednesday as Salvatore Aureliano steered it away from Oyster Bay after the fireworks show. Mr. Aureliano is a brother-in-law of the boat's owner, Kevin Treanor. All of the passengers were thrown into the water, except three children who drowned after being trapped in the cabin as the boat submerged. One was Mr. Treanor's daughter Harlie, 11. The others were David Aureliano, 12, Harlie's cousin, and Victoria Gaines, 7, the daughter of friends of the extended family that arranged the excursion. A funeral for David Aureliano was held on Monday morning. Services for the girls were scheduled for Tuesday. Mr. Aureliano has said that the wake from a passing boat hit the Kandi Won broadside and knocked it over. But Mr. Skrynecki said that the police were still trying to determine the cause. "I'm not certain that the boat will provide all the answers that we're looking for," Mr. Skrynecki said. We don't know exactly what information we'll get when this boat is brought up. But until it is, he said, detectives will not know enough to recommend whether prosecutors should press any criminal charges. To pursue charges of criminal negligence in the deaths of the children, prosecutors would need to determine that the boat's operators failed to perceive the risks they were taking and contributed to those risks by doing something that was seriously blameworthy, like driving the boat too fast or being intoxicated, current and former prosecutors said. James Mercante, a lawyer hired to represent Mr. Treanor by his insurance company, said on Friday that it was not clear that the boat was dangerously overloaded. There is no federal regulation limiting the capacity of a pleasure boat the size of the Kandi Won, a Coast Guard spokesman said. Boaters use a rule of thumb for calculating capacity of boats under 25 feet in length: multiply the boat's length by its width in feet and divide by 15. But the United States Power Squadron, a boating safety organization, says there is no similar guide for yachts.