Claire Knowles, 67, of Concord, was swimming after an inflatable tube in mild current Sunday morning when she suffered a medical emergency returning to shore, New Hampshire State Police said.

A 67-year-old Concord woman died Sunday after suffering a medical event while swimming in the Merrimack River, according to New Hampshire State Police.Marine Patrol officers were called at 11:52 a.m.

The New Hampshire State Police are investigating the death of a Concord, NH woman who died in the Merrimack River on Sunday.