CHICAGO — Authorities searched Friday for a convicted murderer from Indiana who was mistakenly released after a Chicago court appearance, as officials in Illinois admitted they lost paperwork directing them to return him to Indiana.

It turned out Steven L. Robbins didn't even need to be brought to Chicago in the first place, and Cook County officials on Friday also pointed fingers over who was responsible for that mistake.

Robbins, 44, was serving a 60-year sentence for murder in Indiana and was escorted by Cook County sheriff's deputies to Chicago this week for a court appearance in a separate case involving drug and armed violence charges — a case that had actually been dismissed in 2007.

After appearing before two Cook County Circuit Court judges, Robbins was taken to a jail on Chicago's South Side. He was released hours later, instead of being sent back to Indiana to continue his murder sentence. The public was not alerted that he was on the loose for about 24 hours.

Cook County Sheriff Tom Dart on Friday took responsibility for Robbins' release, saying a document showing he should be returned to Indiana disappeared while his deputies were transporting the prisoner, sometime between a Tuesday court appearance and his return to jail after a second court appearance Wednesday. Robbins was released Wednesday evening.

"We're not ducking the fact we dropped the ball. We made mistakes," Dart said. "The public deserves much more. We're going to find out what went wrong here."

But Dart and Cook County State's Attorney Anita Alvarez, both prominent local Democrats, exchanged tense words about who should accept responsibility for having Robbins brought to Chicago from Indiana.

Alvarez said her office had told Dart's office that it didn't need to bring Robbins from Indiana because the drug and armed violence case was closed. But Dart's office proceeded anyway, she said, because of confusion over the outcome of the case and because Robbins demanded to stand trial.

"The Cook County Sherriff's Police, despite the fact that the assistant state's attorney told them that they didn't have to bring him back, they thought it would be better if they did bring him back to get this all cleared up because the guy keeps writing letters demanding trial," Alvarez told reporters.

But Dart said his office sought — and was granted — permission from the state attorney's office to bring Robbins to Chicago. The sheriff showed The Associated Press a copy of the extradition request from September signed by one of Alvarez's prosecutors.

"We can't just go to any state in the country and say 'You know what? We're going to take someone out of your prison and bring him here.' ... They're the ones that signed off on allowing us to go get this guy," Dart said.

Dart also said that because of an antiquated computer system, his office thought an arrest warrant for Robbins in the case was still active, which is why it asked the state attorney's office for permission to extradite Robbins.

"It's our fault but we move 100,000 people a day and it's all done with paper," Dart said.

Federal and local law enforcement officers searching for Robbins were knocking on doors in Illinois and Indiana on Friday, including those of his friends and relatives, the sheriff's office said. The FBI and U.S. Marshals Service offered a $10,000 reward for information leading to his apprehension.

In a late afternoon interview, Dart said there had been sightings of the fugitive and that authorities had been close to catching him.

Robbins, a Gary, Ind., native, was serving a sentence for murder and weapons convictions out of Marion County in Indiana.

Witnesses to the 2002 killing told police Robbins was arguing with his wife outside a birthday party in Indianapolis when a man intervened, telling Robbins he should not hit a woman, according to court documents. The witnesses said Robbins then retrieved a gun from a car and shot the man, Rutland Melton, in the chest before fleeing.

He started serving his sentence in October 2004 and his earliest projected release date was more than 16 years from now, on June 29, 2029.

It is not the first time a prisoner has been mistakenly freed from the Cook County Jail.

In 2009, Jonathan Cooper, who was serving a 30-year manslaughter sentence in Mississippi, was brought to Chicago to face charges that he failed to register as a sex offender.

Prosecutors dropped the charges because, as an inmate, he could not comply with the Sex Offender Registration Act.

A clerk reportedly failed to include the Mississippi sentence information in Cooper's file, and jail staff released him.

Cooper turned himself in several days later.

In a more recent embarrassment for law enforcement officials in Chicago, two convicted bank robbers escaped from a high-rise federal lockup in December by climbing down the side of the building on a rope made of bed sheets and jumping into a cab. Authorities recaptured both men, one of whom remained on the run for about two weeks. Officials have yet to provide a public explanation of the jailbreak.