HOUSTON - The search for a Texas death row inmate who brazenly escaped from the Harris County Jail has become a nationwide manhunt, officials said Saturday.

The Harris County Sheriff's Department continued following up on tips and possible sightings of convicted killer Charles Victor Thompson but none have worked out so far, said Lt. John Martin.

The U.S. Marshals Office is now offering a $10,000 reward for Thompson's capture and has designated him a federal fugitive in order to use its resources to find him.

"We've alerted airports, border officials, other law enforcement agencies," Martin said. "This is an extensive search. We are relying on the public to report any information that they have."

Thompson, 35, of the Houston suburb of Tomball, was condemned in 1999 for the shooting deaths a year earlier of his ex-girlfriend, Dennise Hayslip, 39, of Tomball, and her new boyfriend, Darren Keith Cain, 30, of nearby Spring.

Thompson had been brought from death row to Houston after the Texas Court of Criminal Appeals ordered him resentenced. A new jury sentenced Thompson to death Oct. 28. He was in the county jail until he could be transferred back to prison in Livingston, about 75 miles to the northeast.

Thursday afternoon Thompson was taken to a room in the jail for a meeting with his attorney. The visitor, however, was not Thompson's attorney of record, Terrence Gaiser.

Martin said investigators have determined the other person was an attorney. But his name was not released because he is considered a witness.

"We are not necessarily suggesting he was involved with the escape, but we will be speaking with everybody who had contact with Thompson," Martin said.

After the attorney left, Thompson was alone in the room and he managed to remove his handcuffs and slip off his bright orange prison jumpsuit.

He left the room wearing a dark blue shirt, khaki pants and white tennis shoes, which authorities believe were the clothes Thompson wore during his sentencing. Martin said Thompson somehow smuggled them back to his cell.

Thompson then left the prisoner's booth in the visiting room. Officials don't know if the booth was locked or not.

Once out of the room, Thompson waved a fake ID badge that wasn't scrutinized and said he worked for the Texas Attorney General's office as he passed at least four jail employees at work stations. Thompson was eventually let into the jail's visitor's lobby and from there he walked out of the building and into the street.

Martin said investigators on Friday found the clothing Thompson wore when he left the building. It was located behind one of the sheriff's department's other downtown jail buildings and some effort had been made to hide it, he said.

"It's pretty clear at this point there was somebody helping him," Martin said.

Also found was the fake ID badge he used, which turned out to be an inmate ID card with his photograph issued by the Texas Department of Criminal Justice. Thompson had put a piece of tape over the part of the card that indicates he is an inmate.

Prosecutors accused Thompson of trying to hire hit men to kill witnesses against him as well as members of Hayslip's family.

Martin said members of Hayslip's family have been given police protection.

The sheriff's department's internal investigation of how Thompson escaped also continues.

Martin said while there is no direct evidence Thompson got help from inside the jail, that has not yet been ruled out.

The sheriff's department is also dealing with the public relations fallout from the escape.

"There is no good way to spin this," Martin said. "The point is there were multiple errors on the part of our personnel. This is 100 percent human error that could have been prevented and it wasn't."