A preliminary hearing was rescheduled Monday to Dec. 12 for two 16-year-old boys accused of raping two teenage girls at knifepoint in a Rancho Penasquitos park during the Labor Day weekend.

Leonel Contreras and William Steven Rodriguez have been charged as adults with 16 counts, including kidnapping, forcible rape and sodomy by force. Each defendant faces up to 325 years to life in prison if convicted of all charges, said Deputy District Attorney Wendy Patrick.

The 15- and 16-year-old alleged victims had been attending a family party in the 12600 block of Spindletop Road and walked to a nearby park about 8:15 p.m. on Sept. 3, police said.

At an arraignment in September, Patrick told a judge that the defendants -- both wearing jackets with hoods -- walked past the girls, then came up from behind and immediately ordered them across the street and into a secluded area.

The defendants ordered the girls to take off their clothes and assaulted them for 30 to 40 minutes until the family members of one of the girls started calling out their names, Patrick said.

The assailants threatened the girls before riding off on a bicycle that had been stashed in the bushes, Patrick alleged. As they departed, one of the boys told one of the victims, "Don't scream, I don't want to have to hurt you," according to Patrick.

The girls and the defendants didn't know each other, but Rodriguez lived in the neighborhood where the crimes occurred, the prosecutor said.