Federal prosecutors believe they have firm evidence to suggest R. Kelly transported underage women across state lines for sexual purposes, according to new legal documents.

Lawmakers in New York have more than a dozen flight records, hotel receipts, bank records, medical records and various other business documents, as well as the birth certificates of several women, according to TMZ. They also have Uber records, photos and text messages.

The prosecutors are convinced their evidence will prove the I Believe I Can Fly singer violated the Mann Act, which makes it a crime for people to transport people across state lines for illicit sexual purposes.

Kelly, who is facing criminal charges in New York, Illinois, and Minnesota, is reportedly in talks with top criminal defence lawyer Tom Mesereau in a bid to hire him as his top attorney.

The singer missed a pre-trial court hearing in his sexual abuse case in Chicago, Illinois on Thursday (15Aug19), frustrating prosecutors and the presiding judge, who continued the hearing without him.

Judge Lawrence Flood told Kelly's current lead defence lawyer Steve Greenberg, "He (Kelly) has to be here."

Accusing the hitmaker of declining transport, prosecutor Jennifer Gonzalez said, "The defendant was to be brought to court today. That was all worked out. The sheriffs were going to be bringing him over. As I understand it, he refused transport and so that is why the defendant is not before your honour today."

Greenberg explained that U.S. Marshals had said that moving Kelly from his cell at Chicagos Metropolitan Corrections Center was a "large undertaking".

Kelly's next court date in Chicago is scheduled for 17 September.