A Kentucky disability attorney who stole $600 million from the federal government has disappeared, the FBI said.

Eric Conn pleaded guilty in March to stealing from the federal government and bribing a judge. He was ordered to pay back tens of millions of dollars. His sentencing was scheduled for next month.

The FBI said Saturday that Conn violated the conditions of his bond by removing his electronic monitoring device which prompted the U.S. District Court to issue a warrant for his arrest.

General counsel for the FBI’s Louisville office, David Habich, said that Conn’s “whereabouts are currently unknown.”

Conn started his practice in 1993 and has since built one of the most lucrative disability firms in the country. Known as “Mr. Social Security,” Conn built a persona for himself using outlandish TV commercials.

But Conn's empire crumbled when federal investigators uncovered he had been bribing a doctor and a judge to approve disability claims based on fake medical evidence. As part of his plea deal in March, he agreed to pay the federal government $5.7 million and to reimburse Social Security $46 million. A federal judge ordered Conn to pay $12 million in damages and $19 million in penalties to the government and two former Social Security employees who tried to expose the scheme. And Conn is also facing a liability judgment from a class action lawsuit brought by his former clients, with a hearing scheduled for later this month to determine the damages.

The scandal prompted the federal government to review the eligibility of about 1,500 people receiving benefits, more than half of the people lost their benefits as a result.

The Associated Press contributed to this report.