(CNN) -- A body believed to be the second victim of a boating accident involving a wedding party was recovered in the Hudson River, authorities in Piermont, New York, said Sunday.
Investigators were working to positively identify the body, which is believed to be that of Mark Lennon, Rockland County, New York, Sheriff Louis Falco said.
"We're looking into every single thing," Falco said. "What we're going to do is bring in an accident reconstruction team."
Lennon, who was to have been the best man in the wedding party, and bride Lindsey Stewart disappeared late Friday night when a 21-foot Stingray power boat they were passengers on struck the side of one of three barges lashed together at a construction site near the Tappan Zee Bridge, 25 miles north of Manhattan.
Stewart and Lennon were thrown from the boat. Her body was recovered Saturday, but the search for Lennon continued until Sunday morning when a jet skier called police to report finding a body in the river, Falco said.
Stewart and fiancé Brian Bond, Lennon and three other friends boarded the power boat for what was to have been a short ride on the Hudson River from the village of Piermont in Rockland County to Tarrytown. They had just dined at a restaurant.
Despite suffering serious head injuries, Bond called 911 from the boat, reporting that it had struck an object south of the bridge. The four others who were not thrown from the boat suffered head injuries and were taken to area hospitals.
The barges, which were being used by a contractor who is building a new bridge, had been anchored in the river since around April, said Robert Van Cura, undersheriff of the Rockland County Sheriff's Office.
Boat operator Jojo K. John, 35, was arrested.
"We have probable cause to believe that he operated the boat while intoxicated," Van Cura said.
John was arraigned at an area hospital on one count of first-degree vehicular manslaughter and three counts of second-degree vehicular assault, Van Cura said. More charges are possible, he said.
Van Cura said the operator was not the registered owner of the boat, which may have more than one owner.
Bond was hospitalized at Westchester Medical Center, said Stewart's stepfather Walter Kosik, who visited him Saturday. "He was in no condition to talk."
A spokesman for the medical center said Bond was in fair condition.
"She's supposed to be married two weeks from today," said Carol Stewart about her daughter. "It just can't end like this."
An investigation has begun. "The barge had some lights on it; whether or not it was properly lighted is part of the investigation," Van Cura said.
"On a clear, moonlit night, with the bridge lights on, you can see pretty well," said Tom Sobolik in a telephone interview from aboard his sailboat near the accident site.
The moon was last full on Monday.
But Craig and Celeste Kmiecik said they were boating in the area on Friday night, and it was dark. "There was a moon last night, but you really can't see anything," said Craig Kmiecik.
"The barge was not lit up," said Celeste Kmiecik. "We saw that last night coming back to the marina."
CNN's Alina Cho, Chris Welch and Tom Watkins contributed to this report.