The deaths of Robert F. Kennedy's granddaughter, great-grandson ruled accidental

Robert F. Kennedy's great-grandson was weakened by hypothermia before he and his mother both drowned in a canoeing accident in the Chesapeake Bay, Maryland authorities said Tuesday.

The adult daughter and grandson of former Maryland Lt. Gov. Kathleen Kennedy Townsend went missing on April 3 as they paddled in waters near Shady Side, Maryland, about 25 miles south of Annapolis, officials said. Maeve Kennedy Townsend McKean, 40, was executive director of Georgetown University's Global Health Initiative. Her son Gideon McKean was 8.

Both of their bodies were found days later.

"The cause of death for Maeve Kennedy Townsend McKean was drowning and the manner is accidental," according to a statement by the Maryland Department of Health.

"The cause of death of Gideon McKean was drowning complicated by hypothermia, and the manner is accidental."

A preliminary investigation found that McKean and her son might have been paddling into the bay to retrieve a ball and were unable to get back to shore.

Kathleen Kennedy Townsend, who served two terms of lieutenant governor of Maryland, comes from one of the most famous political families in U.S. history. She’s the oldest daughter of Robert F. Kennedy and niece of former President John F. Kennedy and Edward M. Kennedy.

In a long Facebook post, widower David McKean said his wife was "the brightest light" he had ever known.