Massachusetts Governor Deval Patrick has signed into law a measure giving police chiefs authority to turn down a resident's requests to buy a rifle or shotgun if they believe the person may be a danger. The measure broadens the authority of police, who were already allowed to deny sales of handguns to people who failed background checks. The new measure gives a police chief 90 days to petition a court to deny a firearms identification card to someone the chief believes to be unfit. "This legislation moves us in that direction." House lawmakers passed the measure two weeks ago, overriding objections from gun-rights advocates in the state Senate who had opposed the measure, worrying that police chiefs could abuse the authority to deny firearms to law-abiding citizens.