(CNN) -- Charges against a police officer jailed in a two-state shooting rampage will be formally dropped Wednesday, a prosecutor said.
Brian E. Dorian, 37, was to be released on his own recognizance Tuesday night, Will County State's Attorney James W. Glasgow announced.
"I feel horrible that Brian Dorian went through this," said Glasgow, adding that evidence at the time and identification in lineups merited the charges. "At no time did we stop looking for exculpatory evidence."
A forensic analysis of Dorian's home computer and its activity put Dorian at home at the time of the shootings and verified his alibi, authorities said. The officer also told them he was watching sports programs and using e-mail.
John Dorian, the officer's father, told CNN affiliate WLS he was "relieved" and "never doubted his son."
Dorian's attorneys spoke only briefly Tuesday evening.
"He is relieved but concerned that someone is still out there who killed someone," said David Carlson.
Dorian's boss at the Lynwood Police Department said the officer's "reputation has been damaged and his family and fellow officers have been dragged through the mud."
The state's attorney owes the attack victims, their families, Dorian and Lynwood residents "an apology for rushing to judgment thereby causing a great deal of pain and suffering for everyone involved," Chief Russell L. Pearson said in a statement Tuesday night.
Earlier in the day, Dorian appeared in court via a hookup from the Will County Jail. He did not speak but an attorney entered a not guilty plea, WLS reported.
Several friends and relatives wore T-shirts bearing the message "Free Brian."
"There's an innocent man sitting behind bars and somebody else is running around out there knowing that he got away with it. It's not fair," Jill Aggen, a friend of Dorian, told WLS. "No doubt in my mind. He's not capable of it."
Dorian was arrested Friday in the killing of one person and the wounding of three others in the spree, which occurred south of Chicago, Illinois.
He was held on a probable cause warrant, and bail was set at $2.5 million.
Dorian, who according to WLS has been on medical leave for an injured shoulder the past year, was taken into custody Friday at his residence, said authorities.
The shootings began about 10:30 a.m. October 5 at a construction site near Beecher, Illinois. The gunman killed one worker at the site and wounded two others, police have said.
An hour later and about 10 miles away in Lowell, Indiana, authorities believe the same gunman opened fire again -- this time on a local farmer. Keith Dahl was shot in the left shoulder, arm and elbow, and then was robbed.
Dahl told Lake County (Indiana) Sheriff's Detective Robert Martinez that the gunman approached him on his farm and started a conversation about bees before beginning to shoot.
The gunman was believed to be using a revolver -- possibly a Colt .38-caliber or .357 Magnum -- because no shell casings were found at either scene, Lake County Sheriff Rogelio "Roy" Dominguez said.