PHOENIX—A campaign to force a recall election against the polarizing sheriff of metropolitan Phoenix has failed.

Organizers of the recall effort against Maricopa County Sheriff Joe Arpaio say they didn’t gather the more than 335,000 valid voter signatures needed by 5 p.m. Thursday to force a recall election.

Critics say Arpaio’s office has failed to adequately investigate more than 400 sex-crimes cases, has cost the county $25 million in legal settlements over treatment in county jails, and his office was found by a federal judge to have racially profiled Latinos in his signature immigration patrols

The recall group struggled to raise funds, had to rely on a mostly volunteer workforce to collect signatures and mounted a campaign against a politician who has a base of devoted supporters.

Arpaio supporters had said the sheriff won re-election fairly and that recall organizers shouldn’t be allowed to contest the election simply because they don’t like the outcome. The sheriff, whose campaign fund was depleted after spending more than $8 million during the last election cycle, has cited the recall effort in recent fundraising efforts.

“By their own admission, they have a steep hill to climb,” Arpaio campaign manager Chad Willems said of recall organizers.

Five weeks ago, the group said it had collected 200,000 signatures.

The recall effort began just weeks after the 80-year-old Republican sheriff started his sixth term in January.

Arpaio, through his campaign manager, declined an interview request about the recall effort. In the past, the sheriff has apologized for the bungled sex-crimes investigations and said his office has moved to clear up the cases and prevent a repeat of the problem. He has vigorously denied allegations that his deputies racially profiled people in traffic patrols targeting immigrants who were illegally in the country.