(CNN)Just over a month ago, Kamron Taylor sat in an Illinois courtroom to hear a jury convict him of murder. Early Wednesday morning, Taylor sat in an Illinois jail. Hiding outside his cell. Ready to pounce. When he did, his victim was a correctional officer making his rounds, according to Kankakee County Sheriff Timothy Bukowski. Taylor beat up the guard, put on his uniform and took his keys. He then walked out of the jail's door and into the officer's brown 2012 Chevrolet Equinox SUV. Where the 23-year-old, who was set to be sentenced in May, is now is anybody's guess. The Equinox was discovered around 8:30 a.m. (9:30 a.m. ET) in Kankakee, but without any sign of the convicted murderer who drove it. Looking for Taylor is job No. 1 for authorities. No. 2 is figuring out how he managed to first get out of his cell, then get out of the Jerome Combs Detention Center and on the lam. "The question for us is where did (the county correctional system) break down," Bukowski said. "It looks right now (like) somebody didn't do their job properly." What authorities do know is based on video, other evidence and interviews with witnesses -- namely other inmates at the Kankakee jail. What they don't know is how Taylor got out of his two-man cell, when he should have been locked down. But somehow he did, and hid. "And then when the opportunity arose, he attacked the officer," Bukowski said, noting that Taylor "attacked from the side" around 3 a.m. "Beat him, choked him." He then apparently disrobed the guard, a military veteran and 10-year employee of the corrections department. The guard was left on the jail floor, going in and out of consciousness, for about 35 minutes before authorities -- concerned because the guard hadn't responded to calls -- found him, the sheriff said. "They then called the ambulance and we were notified and put out an alert," added Bukowski. By then, Taylor was gone. He'd pushed a button to notify "master control" that he wanted to leave, which means his identity would have been checked by camera. "We think that because he had the officer's uniform on," the sheriff explained, "that's how he was able to effectively escape." Taylor walked out the door and into the detention center's parking lot, where, authorities said, he clicked the correctional officer's key fob to find the Chevy Equinox. That officer is now in an intensive care unit at St. Mary's Hospital in Kankakee, Bukowski said. The manhunt, meanwhile, continues for Taylor. He has a history of trouble with the law that predates his murder conviction, including an August 2009 sentence of five years, 10 months in Tennessee for robbery and resisting arrest. Taylor was on parole for that crime when he killed a man during a June 2013 botched robbery. A jury convicted him of murder in that incident in late February. After the verdict was read, Taylor sat down, looked back, then got up and ran, according to The Daily Journal in Kankakee. Bailiffs and sheriff's deputies wrestled him to the ground, eventually leading him out of the courtroom as he cursed. Now a $5,000 reward is being offered for information leading to his arrest. The fact that he tried to get away once before and has been involved in fights "raises an alert, I guess," the Kankakee County sheriff said. "But we figure that the people who are locked up in our facility aren't altar boys, and we take certain precautions for all of them," Bukowski added. "And you can't become complacent with anybody, especially murderers." CNN's John Newsome contributed to this report.
Sheriff: The correctional officer is in intensive care after being beaten, choked .
It appears "somebody didn't do their job properly," sheriff says after the escape .
Kamron Taylor also tried to escape a courtroom after being convicted of murder in February .