Boston police have released images of two dresses that investigators believe were purchased by Clark Rockefeller, the man who allegedly kidnapped his 7-year-old daughter during a supervised visit in Boston. Authorities say it is possible the missing girl is wearing one of the two outfits.

Rockefeller is accused of snatching his little girl, Reigh Boss, Sunday during a visit supervised by a social worker. Authorities say he then fled in an SUV driven by another person.

Boston police confirmed to FOXNews.com that the vehicle was found Tuesday and the operator was being questioned.

The 48-year-old divorced father and his daughter Reigh were last seen Sunday night at Grand Central Terminal in New York. Authorities believe Rockefeller, who has used many aliases and has a murky background, may try to leave the country in a recently purchased yacht.

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Rockefeller recently told confidantes that he had procured a 72-foot catamaran called "The Serenity" with $300,000 in gold bullion, according to a report Wednesday in the Boston Herald.

The boat was to carry him to Bermuda or Peru, the paper reported.

Reigh lives with her mother in London. The visit Sunday was the first with her father in several months.

Massachusetts posted an Amber Alert for Reigh, but canceled it Monday after New York City police reported that Rockefeller had been seen the night before at the city's Grand Central Terminal.

Authorities said they believe he may be trying to flee with Reigh on the yacht, possibly to Bermuda. The New York Police Department Harbor Patrol, the Coast Guard and the FBI searched for the yacht Monday in New York City and on Long Island, N.Y.

Boston police issued an arrest warrant for Rockefeller on charges of custodial kidnapping. He also was charged with assault and battery with a dangerous weapon because the social worker was injured while trying to stop the vehicle.

Reigh lives with her mother, Sandra Boss, who works in London as a partner in global management consulting firm McKinsey & Co. and who also is on the board of The Mount, Edith Wharton's estate in Lenox, Mass.

Little has been made public about Rockefeller's background.

Fraser Seitel, a spokesman for the descendants of John D. Rockefeller Sr., said Clark Rockefeller is not a relative of that side of the wealthy family and there is also no indication that the fugitive is a descendant of William Rockefeller, John D. Rockefeller Sr.'s only sibling.

The Valley News, of Lebanon, N.H., reported in 2004 that Clark Rockefeller donated $110,000 to the town of Cornish, N.H., where he and Sandra Boss were part-time residents.

Rockefeller is a former director of Boston's exclusive Algonquin Club, but resigned from the club three months ago, club manager Lassaad Riahi said Monday.

"What I do know is he's a gentleman. He's a kind man. Polite. Very, very intelligent," Riahi said. "I am very shocked."

Click here for more on this story from MyFOXBoston.com.

The Associated Press contributed to this report.