By Ian Simpson

WASHINGTON (Reuters) - Several hundred people have contacted U.S. agents investigating a teacher suspected of molesting boys while teaching at American schools around the world, an FBI spokeswoman said on Wednesday.

The Federal Bureau of Investigation said in April that the suspect, William Vahey, had molested at least 90 boys, whose photos - dating back to 2008 - were found on a thumb drive.

Now deceased, Vahey, 64, had taught at schools in nine countries during an international teaching career that began in 1972. He committed suicide in Minnesota in March, two days after FBI agents in Houston sought a warrant to search the contents of the thumb drive.

"We've been contacted by several hundred individuals from around the globe wishing either to reach out as potential victims or provide information in the ongoing investigation," said FBI spokeswoman Special Agent Shauna Dunlap.

She said the FBI was continuing to investigate Vahey, a registered sex offender, and urged those who have not yet come forward to do so via the agency's website.

Dunlap said that even though Vahey had killed himself, charges still could emerge.

"Just because the subject decides that he's not going to face justice doesn't mean that we're going to stop our investigation," she said.

The thumb drive was given to the FBI by an employee of the American Nicaraguan School, in Managua, Nicaragua, where Vahey taught history and geography.

A complaint filed with the FBI said the USB drive contained pornographic images of boys between the ages of 12 and 14 who appeared to be asleep or unconscious.

When the school employee confronted Vahey, he said he had molested boys his whole life and "reportedly admitted giving the minors sleeping pills prior to the molestation," the FBI said in a statement.

The school fired Vahey in March. The FBI said Vahey had worked at American international schools, which serve the children of diplomats, well-off Americans and local elites, in Nicaragua, the United Kingdom, Venezuela, Indonesia, Saudi Arabia, Greece, Iran, Spain and Lebanon.

At the time of his suicide, Vahey was married and the father of two adult children.

In 1969, Vahey pleaded guilty in California to a child molestation charge and was sentenced to jail and probation, the FBI said. Vahey's conviction required him to record his name with the state of California's sex offender registry for the remainder of his life. However, Vahey had not renewed his registration as a sex offender since 1970.

(Reporting by Ian Simpson; Editing by Barbara Goldberg and Gunna Dickson)