An October trial date has been set for a 36-year-old man accused of committing a series of robberies throughout San Mateo County, including the February robbery and sexual assault of a gas station employee in San Bruno, a deputy district attorney said today.Sione Motuapuaka re-entered a plea of not guilty in San Mateo County Superior Court on Wednesday and the trial was set for Oct. 5, according to Chief Deputy District Attorney Steve Wagstaffe. Motuapuaka is accused of committing armed robberies at various businesses, including a doughnut shop and a sandwich shop, between January and his arrest in mid-February, Wagstaffe said. He faces life in prison if convicted.During the most recent robbery, which occurred around 10 a.m. on Feb. 8, a man entered a San Bruno gas station and brandished a gun at the female employee, according to Daly City police Lt. Jay Morena.He directed the woman into the beverage display cooler in the back of the gas station, where he sexually assaulted her, San Bruno police Cmdr. Marc Catalano said.After the assault, the man left the woman tied up in the back room while he opened the cashier area and even waited on a customer, police said.He then took an undisclosed amount of cash from the register and left the gas station on foot, according to Catalano.The other four robberies happened in January in Daly City and Colma.On Jan. 3, a man robbed a liquor store on School Street in Daly City while displaying a sawed-off shotgun. Two days later, he robbed a flower shop on Hillsdale Boulevard in Colma also armed with a shotgun, Morena said.A doughnut shop on San Pedro Road in Daly City was robbed Jan. 16, as was a sandwich shop in the Skyline Plaza shopping center in Daly City on Jan. 28, according to Morena.Motuapuaka was arrested without incident at his Daly City home Feb. 12 after robbery task force investigators identified him as the suspect by viewing security surveillance videos of him allegedly committing the crimes, Morena said.Motuapuaka was booked into San Mateo County jail on more than a dozen counts related to charges of sexual assault and robbery.A judge determined at a May 5 preliminary hearing there was enough evidence for Motuapuaka to stand trial. He allegedly said he committed the crimes while he was under the influence of methamphetamine, and because he needed the money to support his family, according to Wagstaffe.Motuapuaka remains in custody without bail.