CHICAGO (CBS) — He took an oath to serve, protect and to uphold the law. But a suburban police officer is accused of breaking it.

Edward Karas is a sergeant with the Rosemont Police Department and he is a suspect in connection with at least two armed robberies.

CBS 2’s  Audrina Bigos has the story.

The sergeant was already in trouble before. Rosemont police tell CBS 2 news he was already on administrative leave since June. The department won’t say why but said he was already stripped of his police powers.

40-year-old Edward Karas had been with the Rosemont Police Department since 2005.

Karas and 48-year-old Wright W. Olaughlin are both charged with two counts of armed robbery after Park Ridge police said the duo hit a Shell gas station in Park Ridge Wednesday morning. They they hit another gas station in nearby Norridge.

The men were arrested together around 2:00 a.m. Thursday at a 7-11 on Higgins Road in Rosemont.

“The fact that you do have a police officer involved, whether he’s on administrative leave or not, for some people in the public it diminishes their opinion of the police,” said Rosemont Deputy Police Chief Duane Mellema. “And it makes the job of all the honest, hardworking police officers a little more difficult.”