CHICAGO (CBS) — Authorities have increased the reward for information leading to the arrest of a convicted killer who escaped from a Kankakee jail earlier this week.

Kankakee County Sheriff’s officials said the reward is now $7,500 for information that helps them catch 23-year-old Kamron Taylor, who overpowered a guard at the Jerome Combs Detention Center early Wednesday, donned his uniform, walked out of the jail, and fled in the officer’s personal vehicle.

Taylor abandoned the guard’s vehicle in a driveway in Kankakee, but has not been seen since.

He was awaiting sentencing for his conviction on two counts of first-degree murder, and one count each of armed robbery, residential burglary, and escaping police. In February, a jury convicted him of the June 2013 shooting death of 21-year-old Nelson Williams Jr.

The father of the convicted killer’s victim has said he fears Taylor is coming for him and his family. Taylor allegedly threatened Nelson Williams Sr. and his family after his conviction in February.

“He told us in the courthouse, ‘I’m gonna get you (expletives),” Nelson Sr. said. “As I go home every night, I figured he might ambush me like he did my son.”

Nelson Sr. said he has been told Taylor is a suspect in another murder, but CBS 2 has been unable to confirm that with police.

Police have searched dozens of homes, and followed up on several leads, but their search for Taylor thus far has come up empty.

Kankakee County Sheriff Timothy Bukowski has said a separate investigation is underway into how Taylor managed to get out of his cell and ambush a guard, and then get buzzed through three locked doors at the jail while wearing the officer’s uniform.

Bukowski has said it’s clear to him someone at the jail did not do his or her job, as he was not only missed in a headcount before the escape, but had to pass through tree locked doors, one of which required a visual inspection by camera. He said both Taylor and the guard he attacked are black men with similar builds.

The guard he attacked was beaten and choked unconscious, and was taken to the intensive care unit of a Kankakee hospital, but his condition has since improved.

Authorities believe Taylor has the guard’s service weapon, and should be considered armed and extremely dangerous. He has twice attempted to escape custody before.