US prosecutors have halted an abuse-of-power investigation against controversial Arizona Sheriff Joe Arpaio, without filing charges.
The probe was launched in 2010 over accusations that Mr Arpaio’s office launched a personally motivated corruption case against a judge.
A separate probe into alleged racial profiling by Mr Arpaio continues.
Mr Arpaio, the self-styled “toughest sheriff in the US”, is known for his hard line against illegal immigrants.
“After careful review, we do not believe the allegations presented to us are prosecutable as crimes,” Assistant US Attorney Ann Birmingham Scheel said in a letter explaining the decision to drop the investigation, according to the Associated Press news agency.