The kids were walking along the 5000 block of Brighton Avenue, near Bacon Street, at about 2:15 p.m. Saturday when they were approached by a man who rode up on a gold skateboard and showed them a switchblade-type knife, according to San Diego police Sgt. Ray Battrick.The man, who was identified by police as Terral Blomquist, allegedly demanded money from the two preteens, Battrick said. One handed over some money and the other had no money, Battrick said. Neither was injured.The man rode off and one of the victims called police, Battrick said. Officers found Blomquist nearby and arrested him after a brief scuffle, Battrick said.Blomquist was being held at the San Diego Central Jail on suspicion of second degree robbery, possession of drug paraphernalia, exhibiting a weapon and obstructing a public officer, according to jail records. Bail was set at $50,000.