WILLSBORO (AP) — An upstate New York man and his 3-year-old son died after their kayak overturned on Lake Champlain, state police said Monday.

Patrick Wells, 28, and his son Beckett Wells were on a single-person kayak near the Willsboro Bay boat launch on Friday afternoon when the craft overturned. Both were found in the water unresponsive, according to police.

Police said the deaths of the two Willsboro residents were accidental. Investigators did not know why the kayak overturned.

An autopsy completed Monday determined Patrick Wells drowned due to hypothermia and cold water exposure.

Life vests were found near the victims in the water. Investigators were unsure if they were being worn before the kayak overturned, police said.

The investigation was continuing.