BUENOS AIRES, Argentina — U.S. Sen. Marco Rubio introduced a Senate resolution calling for a “transparent and internationally backed” investigation into the death of Argentine special prosecutor Alberto Nisman.

Rubio, R-Fla., who is a candidate for the Republican presidential race, introduced the resolution on Tuesday for consideration by the Foreign Relations Committee. The resolution noted that Nisman accused Argentine President Cristina Fernandez de Kirchner and her government of covering up Iran’s role in the deadly 1994 bombing of the AMIA Jewish center in Buenos Aires. Nisman’s complaint was dismissed last month on its last appeal.

It also mentions a Nisman investigation into Iranian agents in Latin America that also threaten the United States.

In 2007, a Guyanese man, Abdul Kadir, plotted to blow up John F. Kennedy Airport in New York and was, according to Nisman, “the most important Iranian agent in Guyana,” Rubio wrote in the bill.

Nisman was found shot to death in January in his Buenos Aires apartment hours before he was to present his evidence on the government’s cover-up.

On Wednesday, a board of coroners met for the first time to determine the circumstances surrounding Nisman’s death. Forensic experts have differed about the cause.

Experts have said it will be difficult for the group to establish one unified version of the death. Some experts believe it was suicide, while others say it was murder.

In early March, Nisman’s ex-wife, federal judge Sandra Arroyo Salgado, said that Nisman had been murdered, citing an independent forensic report as proof. But prosecutor Viviana Fein said that she could neither confirm nor discount such claims.