Bill Richardson, an American ambassador to the United Nations who also worked for years trying to win the release of Americans detained by foreign adversaries, has died age 75.
The former governor of New Mexico died on Friday in Chatham, Massachusetts, said a statement from the Richardson Centre for Global Engagement, which he founded to promote diplomacy and peacekeeping.
He became renowned for his skills in helping to bring about the release of hostages and those unjustly jailed around the world.
“He lived his entire life in the service of others, including both his time in government and his subsequent career helping to free people held hostage or wrongfully detained abroad,” said Mickey Bergman, the centre's vice president.
“The world has lost a champion for those held unjustly abroad, and I have lost a mentor and a dear friend,” he added.
Mr Richardson served as US energy secretary and as US ambassador to the United Nations under the Clinton administration.
He made his name meeting people who were not allies to the US, including Iraq's Saddam Hussein and Cuba's Fidel Castro.
In December 1994, when he was visiting North Korean nuclear sites, word came through that an American helicopter pilot had been downed and his co-pilot killed.
The Clinton White House enlisted Mr Richardson’s help and, after days of tough negotiations, the then-congressman accompanied the remains of Chief Warrant Officer David Hilemon while paving the way for Chief Warrant Officer Bobby Hall to return home.
The following year, and after a personal appeal from Mr Richardson, Saddam freed two Americans who had been imprisoned for four months, charged with illegally crossing into Iraq.
More recently, Mr Richardson was involved in efforts that led to the release of US basketball star Brittney Griner in December from a Russian prison after she was convicted of a drug offence.
In private, US officials were sometimes frustrated by Mr Richardson's activism, and expressed concern that it could undermine official efforts.
But as the Richardson Centre said: “There was no person that Governor Richardson would not speak with if it held the promise of returning a person to freedom.”
He was born on November 15, 1947 – the son of a Mexican mother and American father.
He showed an early flair for baseball, and was drafted as a pitcher by the Kansas City Royals but when a professional career in sports did not pan out, Mr Richardson earned a master's degree at Tufts University's Fletcher School of Law and Diplomacy.
Mr Richardson was the first Latino to run for the US presidency, with a fleeting bid in the Democratic primaries in 2007 – a process that eventually yielded Barack Obama as the party's candidate.
