The final suspect believed to be involved in the Sept. 9 Wal-Mart robbery was arrested Tuesday in Chicago.

Robert Storball, 26, of Chicago, was arrested by Chicago Police on a warrant for armed robbery after investigators received a tip about where he was staying in the area. Detectives, part of the fugitive apprehension section of the Chicago Police, found Storball hiding in a house at which he was reportedly staying, said DeKalb Police Sgt. Robert Redel.

It is alleged Storball entered Wal-Mart, 2300 Sycamore Road, at about 1:45 a.m. and confronted an employee with a handgun working in an office, according to a DeKalb Police Department news release. Storball took cash and left the store in a car waiting in the parking lot occupied by three other people, whom were already arrested for the robbery, according to the news release.

Those arrested for the robbery include Richard E. Rogers, 27, Jason M. Alejos, 25, both of Chicago, and Doraelia Romero, 31, of Plano. Romero was a former Wal-Mart employee, and Rogers and Alejos were involved in the planning, but Storball was the only one to enter the store, Redel said.

Storball is being held in Cook County on additional charges and will be sent to DeKalb after the other charges have been dealt with, Redel said.

All four people were charged with armed robbery in the case.

The suspects have extensive criminal histories, and the investigation has involved joint work with Chicago Police, said DeKalb Police Chief Bill Feithen at a Nov. 4 press conference.