East is behind bars on Saturday night, charged with the fatal shootings of two ex-coworkers at Navy Pier earlier this week.
The 36-year-old South Shore resident has been charged with first-degree murder and unlawful use of a weapon by a felon in connection with the Nov. 5 slayings.
East turned himself in a few days later and was arrested after authorities released images of him on public transportation.
Investigators described East as a disgruntled employee who worked for Levy Restaurants, a hospitality and catering company, before he was fired on Oct. 29.
The company said since being hired just over a year ago, East had been reprimanded for multiple verbal and physical aggressions toward his co-workers.
In court, prosecutors said after being let go weeks earlier, East left his South Side home that morning, dressed in his cook's uniform, and used public transportation to go to Navy Pier.
Detectives said that is how he was able to enter the business. Once inside, he went into a private office area near the loading dock.
Prosecutors said he confronted his former co-workers, 51-year-old Lamont Johnson and 47-year-old Peter Jennings, and shot them both in the head.
Other employees eventually found the victims, who later died at the hospital.
Meanwhile, authorities said, East threw the weapon he allegedly used in the murders into the lake before taking public transportation to flee. Chicago Police Department divers recovered the weapon.
Chicago police launched an exhaustive search for the suspect. Police confirmed they had a person of interest in custody on Thursday.
Investigators said the Kenwood High School graduate dressed in several layers of clothes to commit the murders.
Authorities released security and surveillance images of a person, who they said is East, discarding different items of clothing at various times to avoid detection.
Police said East is a convicted felon who was sentenced to eight years in prison for aggravated robbery.
He has no valid FOID card and is not a licensed conceal-carry license holder.
If convicted, East could face a life sentence. He is due back in court next week.
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