Former Hawaii Lt. Gov. Jean Sadako King died Sunday evening, according to family and friends.

She was 87.

King’s death was confirmed by her sister-in-law Ethel McKillop. She declined to disclose the cause of death but said King had been ill for at least a month, and had been under the 24-hour care of hospice workers and her grandchildren.

King, the state’s first female lieutenant governor, served as Gov. George Ariyoshi’s second-in-command from 1978 to 1982, when she broke ranks and made an unsuccessful challenge against him for the top seat.

King served in the state House and Senate before running for lieutenant governor in 1978.

"As the first woman elected to be lieutenant governor of Hawaii, Jean was a true pioneer," Gov. Neil Abercrombie said in a statement this afternoon. "I fondly remember and value the time we served together in the state Legislature."

"Throughout the years, she remained a steadfast advocate for peace and the environment, unwavering in her recognition of our responsibility as stewards of Hawaii’s natural resources," he said.