The FBI is searching for potential victims of a child predator from the U.S. who taught at American schools overseas.

William James Vahey, 64, committed suicide last month after a school administrator in Nicaragua found a thumb drive filled with pictures of over 90 children taken on overnight field trips since 2008, investigators said.

According to NBCNews.com, Vahey confessed to his boss that he had molested boys his entire adult life before killing himself at a Minnesota hotel.

He worked at schools in the United Kingdom, Venezuela, Indonesia, Saudi Arabia, Greece, Iran, Spain, and Lebanon -- attended by children of U.S. diplomats, military personnel, and other citizens working abroad -- since 1972.

"I'm concerned that he may have preyed on many other students prior to 2008," Special Agent Patrick Fransen said in a statement. "I've never seen another case where an individual may have molested this many children over such a long period of time."

FBI officials claim most victims were boys between the age of 12 and 14 and likely went on overnight field trips with Vahey. However, many of them may not even know they were molested as Vahey often drugged his victims. Officials are asking anyone who believes they may have been abused to fill out a confidential questionnaire.

Additionally, Vahey told a school administrator in Nicaragua that he was sexually abused as a child. In 1969, he spent 90 days in jail for child molestation but did not renew his sex offender registration before beginning his work as an overseas teacher.

Authorities told NBCNews.com that they have not discovered any evidence suggesting Vahey shared his photos with anyone else.

"But his suicide left a lot more questions unanswered than answered," Fransen said.