A 3-year-old boy from Dunkirk was missing last night after disappearing from the banks of the Patuxent River in Calvert County.

The disappearance of William Wallace Donaldson touched off a massive search along the Patuxent shore involving various police agencies using dogs, divers, a helicopter and special detection equipment.

The boy vanished about 7:10 p.m. after being handed from a pier into a boat at the end of Deep Landing Road in the Huntingtown area.

Heather Lynch, spokeswoman for the Maryland Department of Natural Resources police, said the boy was wearing a life jacket when passed into the arms of his father, who was in the boat. Once the child was in the boat, Lynch said, the life jacket apparently was removed.

Lynch said the father went into a cabin to turn on a television set and noticed that the child was gone. Three adults were on shore when the child was passed into the boat, she said, but they did not spot anything unusual.

"It's so sad," Lynch said. "So many of these accidents happen in a moment."

As of about 11:30 p.m., searchers still hoped to find the child alive, she said.

It was not immediately clear who owned the 36-foot cigarette boat.

The boy's parents were identified as Darrell and Theresa Donaldson of McCracken Drive in Dunkirk. They had attended a get-together at a house on the Patuxent shore.

Search-and-rescue dogs from the D.C. police department were brought in to search woods in the vicinity of the dock, Lynch said. Animals from the Maryland affiliate of the American Rescue Dog Association also were brought in.

Divers from Prince George's and Calvert joined in the effort, as did searchers from the Maryland State Police barracks in Prince Frederick, the Dunkirk volunteer fire department and the U.S. Coast Guard.