(CBS) -- A Chicago police officer working off-duty as a security guard gets into an altercation and ends up shooting a man.
In a joint investigation with The Chicago Reporter, 2 Investigator Dave Savini learns there is little police oversight of moonlighting cops, and that can lead to expensive investigations and lawsuits.
Chicago Police Officer Kenneth Walker did not want to talk about what he was seen doing while working a second job as a private security guard. He got into an altercation and then shot Marlon Horton.
Horton died outside a Chicago Housing Authority building, says his brother Jerrod Horton.
"He was unarmed," Jerrod Horton says of his brother.
Officer Walker had just worked two shifts in a row -- one as a Chicago cop and one as a private security guard. He allegedly worked 16.5 hours straight when he fired the deadly shot.
"How can you trust his judgement, when someone's working that many hours?" Jerrod Horton says.
The CBS 2 and Chicago Reporter investigation found the city of Chicago is on the financial hook to defend the officer in an ongoing lawsuit, even though the officer was working for a private company. That is because when an off-duty officer identifies themselves as police, the city says it is required to defend them in lawsuits.
"It remains to be seen how much the city might be on the hook for," says Jonah Newman of The Chicago Reporter.
But it could cost millions. Despite this liability, the Chicago Police Department has few rules regulating secondary employment, Newman says.
"They don't collect any info about how many officers are working off-duty, where they're working, what kind of work they're doing," he says.
A U.S. Department of Justice report released in January says a significant amount of alleged police misconduct involves second jobs. The 2 Investigators found that, whether the city is defending the moonlighting officer or not, it also costs money to investigate these incidents, such as in the ongoing case of Khaled Shaar.
When Shaar was working security at a Portillo's restaurant more than two years ago, customer Terry Clarke says, the off-duty police officer repeatedly punched Clarke and used his handcuffs as a weapon.
"He stands behind the badge. That allows him to do some things above the law," Clarke says. Horton's civil lawsuit is pending.
In Horton's case, the Independent Police Review Authority cleared Officer Walker of wrongdoing. Horton's brother wants more rules in place for officers working second jobs.
Some police departments further regulate or ban moonlighting. One requires private companies sign an agreement taking responsibility for any wrongdoing.
According to the Chicago Police Department, any change to its policy would have to be negotiated with the police union.
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