From the Houston Chronicle [1]:

September 11 Commission member John Lehman Thursday criticized so-called "sanctuary" practices in Houston and elsewhere that restrict cooperation between local police and federal immigration officials as an invitation to terrorists looking to enter the United States.

"It is ridiculous that five cities in the United States do not allow local police to cooperate with the federal immigration service," said Lehman, visiting Houston to lobby for Sept. 11 commission report recommendations.

"The terrorists know" which cities have such policies, Lehman said, naming Houston and Los Angeles among those cities.

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[1] chron · com/cs/CDA/ssistory.mpl/front/2722123