Published: Monday, July 11, 2011 1:58 AM EDT

TIVOLI, N.Y. — Four people were killed and two others seriously injured early Sunday when their boat struck a concrete footing in the Hudson River and sank, according to the Dutchess County Sheriff’s Office.

Just before 6:30 a.m., authorities responded to an area very close to the shore near the Dutchess/Columbia County line and determined that a boat — a 19-foot 1999 Chriscraft — carrying six passengers had sunk after hitting the footing.

The sheriff’s office said in a news release that reckless operation and alcohol are suspected, “however the exact causes will not be known for sure until the investigation is complete.”

“The investigation into the accident is continuing and at this time it is unknown exactly what each person’s position was on the boat or what their role was,” the sheriff’s office said.

The boat was traveling northbound, about 10 to 15 yards off the eastern shore, according to the sheriff’s office.

Killed in the accident were: John Uvino, 26, of Saugerties; Robert Macarthur, 27, of Kingston; Deena Cordero, 26, of Kingston and Jay Bins, 41, of Kingston.

The sheriff’s office said Uvino was ejected from the boat, while the three others were still on the boat when it sank.

The four were later recovered with the assistance of several dive teams and marine patrols.

Autopsies will be performed by the Dutchess County Medical Examiner’s Office.

The two other passengers — Joseph Vehnick, 23, of Kingston and Jessica Hotaling, 27, of Hyde Park — suffered serious injuries, but were able to get off the boat and make it to shore.

According to the sheriff’s office, Vehnick was able to get to a phone to call 911.

Vehnick and Hotaling are being treated at area hospitals.

-Doron Tyler Antrim