The union representing 2,500 rank-and-file Phoenix police officers said Tuesday that a new policy requiring the police to ask the immigration status only of people under arrest does not go far enough and could allow illegal immigrants to commit more crimes. The policy announced Friday by Mayor Phil Gordon and an advisory panel applies to misdemeanor and felony arrests but not civil traffic stops. The police would have the option to send written notification to Immigration and Customs Enforcement on people detained but not arrested. Mark Spencer, president of the union, the Phoenix Law Enforcement Association, said a suspect's immigration status was already checked at the county jail under a sheriff's department policy, making the Phoenix policy moot.