ST. PETERSBURG -- Clutching black and white signs, about 30 people gathered outside the St. Petersburg Police Department this morning, criticizing police for what they call the murder of an unarmed teen.

"You can't keep killing our young people and expect nothing to come of it as a consequence," Omali Yeshitela, founder of the International People's Democratic Uhuru Movement, said on the steps of police headquarters.

The Uhuru-led demonstration is a response to the shooting of 17-year-old Javon Dawson, who was shot and killed by a police officer Saturday during a graduation party.

The shooting took place about 10:40 p.m. Saturday during a loud, crowded party at the Shining Light Masonic Lodge, 3100 Freemont Ter. S. The crowd spilled into the streets and blocked traffic, police said.

Outside, police heard gunfire. According to police accounts, the shooter was Dawson, who disobeyed  challenges from officer Terrance Nemeth, then leveled the gun at him. Nemeth opened fire, striking the teen twice. (Click here to read more on police accounts of the shooting from this morning's St. Petersburg Times.)

Outside the Police Department this morning, Yeshitela and Dawson's mother, 38-year-old Yolanda Baker, disputed the police account. They said Dawson and other teens scattered when police arrived. Javon was shot in the back with his hands up, Yeshitela said.

"There were no statements that he had a gun, fired a gun or pointed a gun," he said. "The Police Department is the only one who's said anything about a gun."

Yeshitela said other teens who tried to stop Dawson's bleeding were pepper-sprayed by police. He declined to name those witnesses but said the Uhuru movement is working with the Dawson family, citizens and the legal community and will present its evidence in upcoming days.

Late Saturday, Dawson collapsed and died in the yard, a block from the lodge.

By the time Dawson's mother arrived, authorities had covered his body in a blanket, she said.

"They wouldn't let me see him," Baker said. "That was hard. They covered him up. I guess he was dead."