A $26,000 reward is being offered for information leading to the arrest of three men involved in the armed robbery of Casino Queen that left a security guard was shot early Sunday morning.

Illinois State Police say three men with rifles entered the casino at 2:51 a.m. and fired gun shots, injuring a security guard. The guard was taken to an area hospital and is listed as stable. Nobody else was injured.

The three suspects fled with an unknown amount of money and are still at large. On Monday, the Illinois State Police released three photos of the suspects.

Photos: Police release suspect photos in Casino Queen robbery, shooting

Cahokia Fire Chief Stephen Robbins said he was walking out to the parking lot of the casino with his family when the shots fired inside. He said he worked with MedStar to help the victim.

A spokesperson for the Casino Queen says their security team "is supplemented by armed, sworn officers of the Illinois Gaming Board." They say the casino was evacuated during the incident, and will re-open when the investigation is complete.

A large police presence was surrounding the building when 5 On Your Side's Rachel Menitoff arrived on the scene shortly after the incident. Officers from Madison County, Cahokia, Allerton, St. Clair County and the Illinois State Police were on the scene to help with the investigation.

The Casino Queen partnered with CrimeStoppers to offer the $26,000 reward. Anyone with information should call Illinois State Police at 618-346-3990 or CrimeStoppers at (866) 371 8477. You can also leave a tip for CrimeStoppers with the P3 Tips app.

Photos: Police on scene of reported shooting at Casino Queen