Police on Saturday searched for two robbers who took several bags of express mail from a postal employee behind a City Heights post office, a police sergeant said. The holdup occurred about 6:30 p.m. Friday at 4193 University Ave., San Diego police Sgt. Rich Nemetz said. Two men, one armed with a silver-colored semi-automatic handgun, approached a worker as he was unloading a truck, and demanded that he hand over several canvas bags carrying express mail, Nemetz said. The victim complied, and the bandits fled on foot into alley, he said. One man had curly hair and was last seen wearing a blue shirt and jeans. The other was wearing a dark T-shirt and black shorts, Nemetz said. Mail theft is increasingly linked to identity theft and methamphetamine use.