Caschaus Tate, 20, was ordered detained Tuesday afternoon by a Cook County judge after being arrested Friday for allegedly trying to get rid of Officer Luis Huesca's stolen gun.
According to prosecutors, members of the Great Lakes Regional Task Force and the Chicago Police Department's Investigative Response Team went to a house near 108th and South Hale to talk to a woman about the murder.
Tate, they said, answered the door and told officers to wait because his girlfriend was naked in a back room.
Another officer then observed Tate exit a back window and use a lawn chair to toss an item over the fence. The item was Huesca's gun, which prosecutors said had all but two digits of its serial number scratched off.
Near the lawn chair, prosecutors said, they found the magazine.
Tate is described as an associate of Xavier Tate, Jr., the man charged with Huesca's murder.
Police said he can be seen on numerous surveillance videos from shops near Huesca's Gage Park home.
The FBI now lists Tate, Jr. on its most wanted list and has released a poster describing him and noting a tattoo on the right side of his neck of the word "majesty" under a crown and additional tattoos on his chest and body.
The poster notes he has ties to or may visit Olympia Fields, Champaign and Decatur.
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He is considered armed and dangerous.
The Fraternal Order of Police and a number of other organizations are offering a $100,000 reward for information that leads to his arrest and conviction.
Caschous Tate is due back in court May 15.