CHICAGO (CBS) — A registered sex offender facing federal charges of having sexual contact with a sleeping passenger on an airliner was in the U.S. on an expired visa, according to investigators.

Srinivasa S. Erramilli, 44, of 1972 Dunhill Lane in Aurora, was indicted on Nov. 1 on charges of engaging in sexual contact without the victim’s permission, a federal offense because it happened aboard a plane bound for Chicago from Las Vegas.

He surrendered to federal authorities, and pleaded not guilty on Nov. 4 before U.S. District Judge Sheila Finnegan, who ordered him released on a $4,500 personal recognizance bond.

On June 14, Erramilli allegedly engaged in sexual contact with a sleeping passenger, the federal criminal complaint alleges. It also claims he continued the unwanted sexual contact after the victim woke up.

Before he was released on bond, however, it was discovered that Erramilli, an Indian national, was wanted on an immigration detainer and he was turned over to the custody of Immigration and Customs Enforcement, according to U.S. Attorney’s office spokesman Randall Samborn. ICE alleges his visa was expired.

Erramilli is scheduled for a status hearing on Dec. 7 in Chicago. If convicted of the sex charges, he faces up to five years in prison, and then would be subject to deportation upon his release, Samborn said.

He is listed on the Illinois Sex Offender Registry for a 2002 criminal sexual abuse conviction.