Authorities are still searching for a convicted murderer who was released in error by the York (S.C.) County Detention Center and are offering a $5,000 reward for information leading to the man's arrest.

The York County Sheriff's Office said today it is also continuing to investigate the circumstances surrounding Thomas Aaron Whitlock's release on Monday.

Whitlock, who was convicted in connection with a 2009 murder in Charlotte, was brought to York County for a Monday hearing on a drug possession charge from April 2009. He accepted a plea deal in the case, and was given credit for time he'd already served in the York jail.

At a press conference Wednesday, York Sheriff Bruce Bryant said official paperwork stated Whitlock's case was disposed of in the S.C. county. Bryant said there was no official paperwork stating he was to return to North Carolina law enforcement custody.

Bryant said there is no indication Whitlock tricked anyone to get out of jail. Rather, the error was a lack of documentation, Bryant said.

It is unclear how officials learned of Whitlock's mistaken release, which happened at 3 p.m. Monday. Authorities didn't discover the error until 1 p.m. Tuesday, and didn't notify the public until more than six hours after that.

The delay in alerting the media was intentional and a way to maintain a "surprise element" to capture Whitlock, Bryant said.

Authorities said they realized he’d been mistakenly released as arrangements were being made to return him to Bertie Correctional Institution in eastern North Carolina.

After learning of the error, authorities said they launched an effort to find Whitlock.

“I could go into a lot of discussions that we’ve had as to how this took place,” Bryant said yesterday. “We deal with thousands and thousands of prisoners each year, book close to 7,000 prisoners each year. There has been a mistake made.”

Bryant, who had been away from the office Tuesday afternoon, said he couldn’t comment on department procedures for ensuring an inmate’s identity.

The Sheriff’s Office said Whitlock has an "extensive" criminal history and is now wanted as a fugitive from justice.

Convicted in 2009 Charlotte murder Whitlock was charged in the June 2009 killing of Jamie Thompson, who was found shot on Old Concord Road in Charlotte’s University City area. Thompson died nearly two months later, according to reports at the time, and police began hunting for Whitlock.

Whitlock wasn’t arrested until April 2010, when FBI agents found him hiding underneath a house in Dallas, Texas.

He was convicted of second-degree murder and possession of a gun by a felon in May 2011. He was sentenced to 11-14 years, according to the N.C. Department of Correction.

According to a South Carolina Law Enforcement Division background check, Whitlock was charged and convicted between 1997 and 2009 of several offenses through the York County Sheriff's Office, the Rock Hill Police Department and the S.C. Highway Patrol, including assault and battery of a high and aggravated nature, burglary, robbery, failure to stop for a blue light, and various drug charges.

The Sheriff’s Office, along with the N.C. Division of Adult Correction and other law enforcement, are working together to find Whitlock. Authorities said he has relatives in Rock Hill. At the time of his incarceration, his address was listed as Dallas, Texas.

“It’s possible he could be anywhere,” Bryant said Tuesday. “That’s the reason we’re asking for the public’s help.”

Authorities said Whitlock is 5 feet, 11 inches tall and 144 pounds, and should not be approached. Anyone with information about his whereabouts is asked to call the Sheriff's Office at 803-628-3059 or Crime Stoppers at 1-877-409-4321.