Tucson police are asking for help in locating a vehicle tied to the killing of a teen Saturday night.

Antonio Flores, 17, was shot and killed by an unknown person or persons who were traveling in a "greenish-colored sport utility vehicle, van or crossover-type vehicle," said Sgt. Maria Hawke, a Tucson Police Department spokesman.

The year of the vehicle is not known.

The incident began shortly after 10 p.m. at a Circle K at South Campbell Avenue and East Drexel Road. Flores, along with five others, were in a Chevrolet Silverado parked in the lot of the convenience store when a dark -colored vehicle approached the truck, Hawke said.

One of the occupants fired an unknown projectile, possibly a BB-gun pellet or CO2 charged weapon, at the Silverado, said Hawke in a news release.

The dark-colored vehicle left the Circle K parking lot and headed west on East Drexel Road. The occupants in the Silverado followed in an effort to get a license plate number of the unknown vehicle, said Hawke.

The truck caught up to the vehicle at Drexel and South Copper Plate Avenue when multiple gunshots were fired at the truck, striking Flores at least once, said Hawke.

Homicide detectives believe firearms shot during the incident were "long-gun type weapons, possibly shotguns and/or rifles," Hawke said.

The dark-colored vehicle left the area, and was last seen traveling south on South Copper Plate Avenue.

The truck continued traveling west on Drexel Road, and the occupants flagged down an officer at South Park Avenue, near Drexel, Hawke said.

They told the officer that Flores was shot and was in the bed of the truck. The officer called for additional units, and began to administer CPR to the teen until Tucson Fire Department paramedics arrived and began to treat Flores. Flores was taken to a hospital where he was pronounced dead shortly after 11 p.m., Hawke said.

No other persons in the truck were injured.

Police do not know the identities of the occupants in the dark-colored vehicle, or the motive for the shootings. Anyone with information is asked to call 911 or 88-CRIME.