Apu began working at the Kwik-E-Mart during graduate school to pay off his student loan, he stayed afterwards as he enjoyed his job and the friends he had made. He remained an illegal immigrant until Mayor Quimby proposed a municipal law to expel all undocumented aliens. Apu responded by purchasing a forged birth certificate from the Springfield Mafia that listed his parents as American citizens Herb and Judy Nahasapeemapetilon from Green Bay, Wisconsin, but when he realized he was forsaking his origins, he abandoned this plan and instead successfully managed to pass his citizenship test with help from Lisa and Homer Simpson. Thus, he refers to himself as a "semi-legal alien".