A man has been charged with the armed robbery of a 7-Eleven store early Monday in west suburban St. Charles.

Ronald L. Medlin, 46, of the 6N800 block of Thompson Avenue in St. Charles, was charged with a felony count of armed robbery and was held on $500,000 bail at the Kane County Jail, St. Charles police said in a statement Wednesday.

About 3:20 a.m. Monday, a 7-Eleven at 2400 E. Main Street was reported robbed by a man who walked into the store and pulled a folding knife on a clerk, police said. The clerk gave the robber money from the register and several packs of cigarettes. He ran north after the robbery.

The clerk told investigators he noticed a suspicious vehicle earlier in the night and gave them the license plate number, police said. They tracked the vehicle to a local business and, through the owners, determined the suspect was an employee. Medlin was later taken into custody.

Medlin is also suspected of two additional armed robberies later that night again in St. Charles and in Elgin, police said. The robberies were under investigation and charges had not been filed in those cases.