DENVER — In September 2008, a Guatemalan immigrant named Francis Hernandez sped his S.U.V. through a busy Aurora intersection and plowed into a pickup truck, knocking it into an ice cream parlor.
Three people were killed, including a 3-year-old boy.
Mr. Hernandez, as it turned out, was in the country illegally and been arrested more than a dozen times over the years, but had managed to elude deportation.
A task force recommended that Colorado institute a federal background check program called Secure Communities, which helps the authorities check an arrested person’s immigration history through a government database, for possible deportation.
Now, as Gov. Bill Ritter Jr. weighs whether to use Secure Communities, already in effect in 480 jurisdictions in 27 states, immigrant rights groups have been privately pushing him to reject the program. Critics say it promotes racial profiling by the local police and would undermine trust between immigrants and law enforcement, in a state that has particularly strict immigration laws.