Investigators are continuing their search for a Fairhaven man who may have fallen overboard during a Vineyard-bound trip of the New England Fast Ferry on Monday.

A team of investigators that includes Island and mainland police, the U.S. Coast Guard and the New Bedford Port Security Authority searched this week for 28-year-old Walter P. Tyler who boarded the 1 p.m. high-speed passenger ferry from New Bedford to the Vineyard but reportedly never arrived.

Fairhaven police chief Gary F. Souza told the Gazette yesterday that surveillance cameras showed Mr. Tyler boarding the vessel in New Bedford although cameras at the Vineyard Haven terminal do not show him getting off. The film shows 26 passengers getting onboard, but only 25 disembarking the vessel, the chief said.

Mr. Tyler’s bicycle was later found abandoned on State Pier in New Bedford, Chief Souza said.

Fairhaven police boats have searched the waters of Buzzards Bay since Tuesday, and the U.S. Coast Guard has also contributed boats to the search efforts. Chief Souza said current weather and sea conditions have limited the search to Buzzards Bay, although it may be widened to include Vineyard Sound in the coming days.

The chief said he has asked the state police to search the Elizabeth Islands. The high-speed ferry passes through the islands en route to the Vineyard.

Chief Souza said investigators are going through the passenger manifest and contacting passengers to find out if they remember seeing Mr. Tyler on the boat.

“If we can pinpoint when, exactly, he was last seen, it may help us to narrow our search,” he said.

Chief Souza said the investigation was being classified as a search for a missing person and not to recover a body. He said Mr. Tyler was a Navy veteran and strong swimmer who had been trained for cold water survival.

“We aren’t going to rule out anything at this point . . . considering the water temperatures and [Mr. Tyler’s] experience in the water it is very possible he was able to swim to shore,” he said.

Tisbury police chief John Cashin said the Tyler family contacted him on Tuesday and asked him to check whether Mr. Tyler arrived on the 1 p.m. ferry the day before. Chief Cashin later told the family there were indications Mr. Tyler boarded the ferry in New Bedford, but there was no evidence of his arrival in Vineyard Haven.

Chief Cashin said he has received information that Mr. Tyler may have left a note and had a history of depression, although there is debate over that report.

Chief Souza said he could not comment on whether a note was found, and several of Mr. Tyler’s family members have denied he was depressed.

“We don’t believe that, he was in good spirits,” said Jeremy Tyler, Mr. Tyler’s brother. “There is nothing to indicate he was planning anything . . . we don’t know what happened.”

Jeremy Tyler was one of several family members who have searched for Mr. Tyler since he first went missing Monday. Several family members traveled to the Island Tuesday and pinned up missing persons posters at Five Corners and other parts of the Island.

On Wednesday, family members chartered a private plane to fly between New Bedford and the Vineyard to search for Mr. Tyler.

Jeremy Tyler said his brother was an especially strong swimmer who would know what to do if he fell into the water. He said his brother served in the Navy for four years after graduating high school and later joined the Merchant Marines where he worked on tugboats.

“If he’s out there we’ll find him . . . we just need help. We are asking that people pay special attention to the beaches and nature trails — and to keep an eye out on the waters,” Jeremy Tyler said.

New England Fast Ferry manager Michael Glasfeld said at the request of the Tyler family he was deferring questions to the Fairhaven police department. Mr. Glasfeld said there has never been a reported injury or missing person since the New England Fast Ferry company was established four years ago.

Generally speaking, Mr. Glasfeld said, the railings of the boat are built to meet all safety guidelines. He said it would be difficult for someone to fall off the side, even during a storm or extreme weather conditions.

Mr. Tyler was last seen wearing a light blue plaid, long-sleeved T-shirt, gray pants, sandals and a dark blue Navy baseball cap with the words “U.S.S. Stump” on the front. He is described as being 6’1” tall and 220 pounds.

Anyone with information is encouraged to call the Fairhaven Police detective division at 508-997-7421.