ST. PAUL (AP) -- A federal judge has certified a lawsuit challenging the constitutionality of the Minnesota Sex Offender Program as a class action on behalf of everyone committed to the program.

U.S. District Judge Donovan Frank ruled Tuesday that the lawsuit meets the legal requirements to be certified as a class action. He pointed out that the proposed class includes about 600 people who've been indefinitely committed to the program, and he concluded that addressing each case individually would be an enormous drain on legal resources.

Frank writes that they all face an identical process for treatment and possible release. He says they all raise similar allegations of a lack of realistic opportunities for earning their freedom. And says they all have sufficiently similar legal interests for their cases to go forward together.