Investigators warned officials at the National Western Complex that the dance party held at the Complex Saturday was actually a rave, 7News learned. Jared Snyder, 19, was struck and killed early Sunday morning after he apparently removed his clothing and sat down in traffic on Interstate 70, officials said. Officials have speculated that Snyder attended a rave at the nearby National Western Complex. Snyder was hit by a truck shortly after 3 a.m., police said, a half hour after police cleared out the party. The driver of the truck left the scene. Nude Man Killed In Hit-And-Run "We had two people call in on an unclothed male party sitting ... in the middle of westbound I-70. Whoever hit this party took off without rendering the aid necessary," Virginia Lopez, of the Denver Police Department, said. Police were looking for a dark-colored Dodge or Ford heavy duty pickup. Anyone with information was asked to call Denver police. Lopez said that the nearby rave was monitored by undercover and uniformed officers. Nine people were arrested at the rave for the sale and possession of a controlled substance, one for possession of marijuana, two for giving false information, and one on an outstanding warrant. Officials speculated that Snyder was under the influence of drugs at the time of the accident. "There's a very high likelihood that he was under the influence of one or more of those drugs -- whether it's ecstasy or another hallucinegenic -- there are a lot of them out there," Dr. Kerry Broderick, of Denver Health Medical Center, said. After the hit-and-run accident, the victim was taken to Denver Health Medical Center and pronounced dead at 3:40 a.m., officials said. Marvin Witt, a spokesman for the Stock Show, said that he did not want to comment on the accident until after it was known if Snyder attended the rave party. Stock show officials have said that the organizers of the party went through all the proper channels. How Do You Keep Teens Off Drugs? The party had about 3,500 attendees, according to Virginia Lopez of the Denver Police Department. The National Western complex was leased out for the event under an agreement that there would be no alcohol or drugs, 7News anchor Thomas Drayton said. "Our officers where there. We did not let anyone in the door that possibly even smelled of the slightest amount of alcohol. They were turned away at the door," Lopez said. "I just think, 'What a waste, what a waste,'" Broderick said. "This young person -- their whole life was ahead of them -- and they think they are just having fun at a party, and it's over with, it's gone," Broderick said. The complex is owned by the city, but city officials are not in charge of booking events.