Updated

Authorities continued their search Wednesday for a convicted robber George Hyatte (search) and his wife, who officials say shot and killed a corrections officer outside a Tennessee courthouse the day before.

According to the Tennessee Bureau of Investigations (TBI), people from 15 states have called to report possible sightings, but none of those claims have been confirmed. Likewise, officials could not substantiate earlier news reports that the pair had been spotted in North Carolina.

One potentially promising tip came out of Kentucky, where police were told that the couple had stopped at an Econo Lodge motel in the town of Erlanger, FOX News has confirmed. U.S. Marshals found the room where the Hyattes allegedly stayed empty, with no sign of blood. Cops took possession of a van parked at the motel.

Wednesday afternoon there appeared to be a break in the case, when Hamilton County Sheriff John Cupp told The Associated Press that authorities knew the location of George Hyatte. However, TBI was quick to deny Cupp's statement and called it irresponsible.

Cupp had said Hyatte's location was not within 100 miles of Hamilton County, but would not elaborate.

In a news conference Wednesday, Jim Moore (search), TBI's special agent-in-charge, said that county officials could not confirm reports that one or two other inmates escaped with George Hyatte. Moore also said there was surveillance video of the parking lot shooting and escape.

When asked by FOX News why the maximum security prisoner was not better guarded, Roane County Sheriff David Haggard replied, "I don't think anything could have been done unless you were a mind reader."

TBI spokesman Jennifer Johnson instructed anyone who sees the suspects to call 911 or 1-800-TBI-FIND. She confirmed that two vehicles were used during the escape.

Police believe the suspects were at some point driving a beige or gold 2000 Chevy Venture.

Hyatte was headed back to prison from a court appearance Tuesday in handcuffs and shackles when his wife, Jennifer Hyatte (search), drove up and fired at the two corrections officers escorting her husband, Kingston Police Chief Jim Washam told FOX News.

"Mr. Hyatte hollered 'Shoot him!' She opened up fire on the officers, hitting one in the abdomen," said Kingston Police Chief Jim Washam.

One guard, Wayne "Cotton" Morgan, was killed; the other was not identified.

George Hyatte, an eighth grade dropout, has a long criminal career and has escaped from law enforcement at least five times before this incident, FOX News has learned.

"It was just a 'Bonnie and Clyde'-style shootout," Mark Gywn, director of the Tennessee Bureau of Investigation (search), said Wednesday on ABC. "These people are very desperate and don't have anything to lose at this point."

The bloody escape set off an extensive search that Gywn said would continue until the couple is captured.

"We will be looking for them, running leads until we find them," he said.

George Hyatte, 34, was at the courthouse to plead guilty in a deal with prosecutors over an armed robbery charge, Washam said.

His wife is a 31-year-old nurse who had been fired from her job at a prison in Tiptonville after it was suspected she was having a relationship with Hyatte, Corrections Department spokeswoman Amanda Sluss said.

Immediately after the shootout, helicopters circled over this eastern Tennessee town and schools — open for student registration — were locked down.

The Ford Explorer driven by Jennifer Hyatte was later found abandoned with blood on the driver's side, and police think she may have been wounded by a shot fired by the other officer during the attack, Washam said. Authorities believe the pair later switched from the SUV to a van.

Gywn said medical facilities in the area had been contacted and told to notify the police if either of the Hyattes came seeking treatment.

Washam said authorities were preparing murder charges against the couple.

"We do have leads coming in on possible whereabouts, possibly some family members that may be hiding them out. We're trying our best to coordinate those," Washam said. "Right now, we can't say if they had any help."

George Hyatte, two years into a 35-year sentence on robbery and assault charges, "is extremely violent, and he has no care or concern on what he does to anyone," said Rhea County Sheriff's spokesman Jeff Knight.

Witness C. G. Gray said he and his wife were about 50 feet from the prisoners when they heard shots. He said Morgan, who was not wearing a protective vest, never got his gun out of his holster.

Morgan, 56, died at the University of Tennessee Medical Center (search) in Knoxville, about 30 miles east, hospital spokeswoman Lisa McNeal said.

The Associated Press contributed to this report.