Around 12:15 a.m. Thursday, a man believed to be in his 30s was found with stab wounds and transported to the Foothills Hospital.
Two other men were later located with stab wounds, but both have been released from hospital.
One of the men and two others were brought in for questioning, but have been released and now police are asking for anyone with information or video to come forward.
Police believe it was a targeted attack.
Stampede officials say they will be increasing bag checks on its grounds.