TULSA, Okla. (AP) -- A police helicopter that happened to be near a Tulsa events center Saturday night when a gunman shot and wounded five people at a Hmong New Year's festival spotted a suspicious vehicle driving away from the scene, which eventually led to the arrest of two suspects, authorities said. Police Capt. Mike Williams said both suspects, like those celebrating inside the Green Country Event Center, are Hmong -- an Asian ethnic group mainly from Laos. He said investigators hadn't determined a motive for the attack, but that both men would be charged. A witness, Chong Bee Xiong, said there were at least 200 people at the celebration, which he equated to Thanksgiving in America. He said people were lined up to get dinner when four or five shots ring out, sending everyone scattering. "The people started screaming, yelling, running. We don't know what happened," he said. Xiong said he didn't get a look at the shooter and couldn't imagine why someone would open fire at the gathering, which the Hmong community has held at the events center for the past several years. He estimates that there is a Hmong population in Tulsa numbering between 3,000 and 4,000. "Nothing's ever happened like this," he said. "We just have to wait for the police. People who came to the party, they are good people. We don't know what kind of problems (the shooter had) or what caused it. We just had no idea." Five people, all of them Hmong, were wounded in the attack and taken to hospitals. Two had been shot in the torso and the other three were shot in the arms or legs, Williams said. He said one of the people shot in the torso was in critical condition, and another victim could lose a leg. The suspects were arrested shortly after the attack, which happened at around 8 p.m. A police helicopter that was in the area spotted a car driving away from the scene with its headlights off and notified officers on the ground, who pulled it over. The suspects had thrown clothes and a semi-automatic handgun believed to have been used in the attack out of the vehicle, Williams said.