John Ashe, of Antigua and Barbuda, served as U.N. General Assembly president from September 2013 to September 2014. (Richard Drew/AP)

John W. Ashe, a former U.N. General Assembly president and U.N. ambassador for the twin-island Caribbean nation of Antigua and Barbuda who faced criminal charges in a bribery case, died June 22 at his home in Dobbs Ferry, N.Y. He was 61.

Mr. Ashe’s death was an accident caused by neck trauma while lifting a barbell, a medical examiner concluded Thursday.

“Despite the many as yet unproven accusations made against him, Mr. Ashe was for many years a hard-working and popular member of the diplomatic corps in New York and at the United Nations,” Mogens Lykketoft, the current U.N. General Assembly president, said in a statement.

Mr. Ashe served in the largely ceremonial post of president of the 193-nation assembly from September 2013 to September 2014. He was accused last year by U.S. federal authorities of turning the position into a “platform for profit” by accepting more than $1 million in bribes.

Preet Bharara, the U.S. attorney for the Southern District of New York, charged in a complaint that in return for the money, Mr. Ashe “supported these businessmen’s interests within the United Nations and with senior Antiguan government officials.”

The alleged conspiracy also involved six others, including a billionaire Chinese real estate mogul, two diplomats and a humanitarian organization officer. Several of the defendants have pleaded guilty over the past several months.

Mr. Ashe pleaded not guilty to the charges, and his attorney Jeremy Schneider had said he would be vindicated. It wasn’t clear how Mr. Ashe’s death would affect the bribery case.

John William Ashe, whose father was a police officer, was born in St. John’s, Antigua and Barbuda, on Aug. 20, 1954. He graduated from Saint Mary’s University in Nova Scotia and received a master’s degree in electrical engineering from the Technical University of Nova Scotia. He also held a doctorate in bioengineering from the University of Pennsylvania.

He joined the foreign service in 1989. As a diplomat, he was heavily involved in sustainable development issues, taking leadership roles in some of the major U.N. environmental agreements.

“We only have the planet we live on, and if we are to leave it in a reasonable state for the next generation, the quest for a safer, cleaner, and more equitable world is one that should consume us all,” Mr. Ashe said in a U.N. release.

In 1996, he married Anilla Cherian, an environmentalist whom he met in Nairobi two years earlier at a conference on biological diversity, according to their wedding announcement in the New York Times. They had children, but a complete list of survivors could not be immediately determined.