Updated: Oct. 8, 2010, 3:58 p.m.

JOLIET, Ill. (CBS) – A Lynwood police officer is being held on $2.5 million bond in a two-state shooting spree, which left a man dead and two others wounded in Illinois and Indiana.

Brian Dorian, 37, of Crete, a Lynwood police officer currently on medical leave, was arrested by Will County Sheriff’s police on a charge of first-degree murder.

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Dorian was arrested about 1 a.m. at a home in Lynwood, according to Lake County, Ind., Police Chief Marco Kuyachich.

Lynwood police found Dorian’s truck in the village after they got a tip. Lynwood Police Deputy Chief Szymanski would not reveal the location where the truck was found, but said he believed Dorian already was in custody at that time.

“It’s always law enforcement’s worst nightmare when someone within the law enforcement community chooses to break the law,” Will County State’s Attorney James Glasgow said at a news conference to announce the charges. Authorities credited the public with helping to apprehend the suspect.

A police source tells CBS 2 that Dorian was a police officer in south suburban Lansing from 2003 to 2005, where he was described as “low-key” and never had any disciplinary issues.

After 2005, Dorian went to work for the Lynwood Police Department. Szymanski said Dorian has been with the department since 2005 but that he has been on medical leave for a shoulder injury since October 2009.

Officers who worked with Dorian from 2003 to 2005 said they were “shocked” and “blown away” by the news about Dorian, the source said.

There is nothing in Dorian’s past to suggest this type of behavior was possible, the source said.

Dorian’s arrest came one day after the Will County and Lake County, Ind., sheriff’s departments announced the formation of a joint task force to search for the gunman, and released a new sketch.

It is not known whether the latest composite sketch played a role in the location and arrest of a suspect.

During the manhunt, sheriff’s investigators were reportedly stopping any vehicle that even remotely resembled the Chevrolet Cheyenne pickup truck the suspect was seen driving after the shootings.

The gunman shot two construction workers near Beecher, Ill., killing one, and then shot and wounded a farmer in Lowell, Ind. He has been on the loose since Tuesday.

Two of the victims have been hospitalized since the Tuesday morning shootings. Farmer Keith Dahl, 62, is recovering from multiple gunshot wounds at St. Anthony Medical Center in Crown Point, Ind. He is expected to recover. Dahl survived the second of the two shootings by playing dead.

Also still hospitalized is Garza, who was initially taken to Advocate Christ Medical Center in Oak Lawn in very critical condition. He was wounded in the first of the two shootings, which left another worker, Rolando Alonso, 45, of Hammond, dead.

In the first shooting Tuesday morning, Alonso, Garza and a third man were working on a repair job at a burned-out farmhouse at Stony Island Avenue and County Line Road near Beecher. The suspect drove up and asked about buying the place, then drove off.

A short time later, the man returned and asked about building materials. Then suddenly, without warning, he pulled out a .38 or .357 revolver and started shooting. Alonso, a father of 10, lost his life on only his second day on the job.

The killer also opened fire on a third construction worker, who escaped into a cornfield and called 911.

In the second shooting, the suspect approached Dahl at his farmhouse at near 201st Street and Cline Avenue, and asked for his wallet. Dahl refused. The suspect then said something about honeybees in the area, pulled a gun and shot Dahl three times; in the shoulder, the left arm and the elbow. He then robbed him. Dahl played dead and the suspect drove off.

Dorian’s history includes a conviction for speeding after a 2006 traffic accident in which a teenager was killed.

According to an attorney involved with the case, Dorian was driving a pickup truck more than 80 mph in a 55 mph zone on a Will County road when 17-year-old Dylan Drapeau pulled his car out into the path of Dorian’s pickup truck. Dorian, who did not have a stop sign, attempted to avoid a collision but could not, said Gregory DeBord, a former county prosecutor.

At the time, the boy’s family pushed for prosecutors to charge Dorian with reckless homicide, but DeBord said after an investigation that include an accident reconstruction, it was determined the only thing Dorian could be charged with was speeding. He said there was no indication that either of the two drivers had alcohol or drugs in their systems, and Drapeau failed to yield to traffic when he pulled his car into the intersection.

In 2008, the then chief of police in Lynwood, defended the investigation into the accident and the conclusions. David Palmer told the Chicago Tribune that Dorian admitted he was speeding and that he was doing so in an effort to rush for repairs after the “check engine” light started flashing.

After the accident, Dorian said he received harassing phone calls and threats that left him fearing for his life, Dorian’s neighbor in nearby Crete, Robin Schmitz, said. She said he was clearly shaken.

“But, she added, “He seemed to have gotten over the accident.”

CBS 2’s Mike Puccinelli, WBBM 780’s John Cody and The Associated Press contributed to this report.

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