The state of Massachusetts joined Illinois and New York in pulling out of the federal Secure Communities program.
The program checks the fingerprints of all persons booked by the police against the files of F.B.I. and the Department of Homeland Security.
The governors of the states say the purpose of the program is to find and deport serious criminals. Instead, advocates say, it is sweeping up illegal immigrants who had not committed crimes.
For example, Figures from the city of Boston show that 54 percent of the people deported had no criminal convictions. Only one in four had committed a serious crime.
The federal government says that states must participate in the program by law. It is in effect in 1,331 local governments in 42 states. It must be in all the states by 2013.