(CBS/AP) DENVER - The first marijuana celebration in Denver since Colorado legalized the drug for recreational use took a violent turn on Saturday, when gunfire erupted, injuring three people, according to CBS Denver station KCNC.
The gunfire during the open "4/20" gathering wounded a man and a woman, not fatally, and a third person was grazed by a bullet, according to the station.
A Denver police official, Sonny Jackson, said authorities are looking for two suspects. Officials are also asking those who were at the scene to provide photos and videos. Reports also say the reason for the shooting is unknown.
According to reports, witnesses describe the scene as "jovial" until the gunshots were heard, driving the attendees into panic. According to KCNC, Travis Craig, a witness who saw one of the victims bleeding, helped the man by using his belt as a tourniquet.
"I saw him fall, grabbing his leg," said Craig.
Authorities said earlier in the week that crowd security was a priority in the wake of the Boston marathon bombings, says CBS Denver.
Another witness, Stephanie Riedel, said "We were all having a good time and I was in the mind frame of, we're here at a peace gathering. I thought it was some guys playing," reported KCNC.
Denver police are now looking for one of the suspects shown in a still from the video. They are offering a cash reward of $2,000 for information leading to his capture.