A former University of Southern California professor arrested in Mexico for alleged sex crimes involving two children in the Philippines has been deported to the United States after a Mexican citizen recognized his picture in the newspaper and informed the U.S. Embassy, federal authorities said Wednesday.

Walter Lee Williams, 64, will appear in a Los Angeles federal courtroom Thursday to face charges of sexual exploitation of children and traveling abroad for the purpose of engaging in sexual acts with children. He was placed on the FBI's Ten Most Wanted list on Monday.

A tip from a Mexican citizen who saw a photograph in a local newspaper and contacted the U.S. Mexico City Embassy led to Williams' arrest by Mexican authorities. The tipster is eligible for the $100,000 reward.

Williams is suspected of traveling to the Philippines to engage in sex crimes with children, authorities said Wednesday.

Prosecutor Gaspar Armando Garcia Torres said in Cancun, Mexico, that Williams was captured late Tuesday while drinking coffee near a park in the resort town of Playa del Carmen.

Garcia Torres said it wasn't clear how long Williams had been living in Playa del Carmen and that the fugitive also had an address in nearby Cancun, where he was taken and turned over to Mexican immigration officials.

Garcia Torres did not say whether Williams is suspected of committing any crimes in Mexico.

Evidence indicates that Williams is believed to have at least 10 alleged victims including the two 14-year-old boys cited in a federal indictment, said FBI spokeswoman Laura Eimiller.

And investigators believe he has more victims. Authorities also have not ruled out additional charges in the case as evidence shows Williams expressed an interest and pursued victims younger than 14 years old, Eimiller said.

A federal arrest warrant was issued for the former Palm Springs, Calif., resident in Los Angeles in April, according to the FBI website.

The four-count indictment alleges Williams traveled from Los Angeles to the Philippines in January 2011 to engage in sex acts with two 14-year-old boys he met online in 2010, the U.S. Department of Justice said in a statement Monday.

“He allegedly engaged in sexual activity via Internet webcam sessions with these boys and expressed a desire to visit them in the Philippines to have sex,” it states.

While in the Philippines, Williams allegedly engaged in sex acts with both boys and produced sexually explicit photos of one of the boys, bringing it back to Los Angeles County. Williams fled the Los Angeles area about a week after returning from the Philippines, the statement said.

Federal authorities believe Williams fled to Mexico once he learned of the investigation against him, according to court documents filed to seal the indictment until he was taken into custody.

Until February 2011, Williams was a tenured professor at the University of Southern California where he taught history, anthropology and gender studies.

“USC is fully cooperating with the FBI investigation,” the university said in a statement. “The FBI has informed us that at this time there is no evidence that any of his alleged illegal activities were associated with the university or took place on campus.”

Williams was also affiliated with the Buddhist Universal Association of Los Angeles according to the FBI.

“Williams has an extensive history of travel throughout the South East Asia region, specifically the Philippines,” the FBI said. “He has reportedly resided in Indonesia, Polynesia and Thailand.”

The FBI said he may have also traveled to Peru.

“I analyzed the computers and the camera that belong to Williams and found child pornography,” said Special Agent Jeff Yesensky, in a video about Williams posted on the FBI's website Monday to bring attention to the case.

“He preys on the most vulnerable children,” Yesensky added. (AP)