PHOENIX — Prosecutors declined to file criminal charges against a Maricopa County sheriff’s detective accused of padding his overtime pay during a secret investigation that critics say targeted a judge presiding over Sheriff Joe Arpaio’s racial profiling case.

The Arizona Attorney General’s Office said in a report made public Wednesday that there wasn’t enough evidence to bring charges against Sheriff’s Detective Brian Mackiewicz on allegations that he was on dates with women when he was claiming the overtime.

The allegations stemmed from an investigation launched by Arpaio’s office months after U.S. District Judge Murray Snow concluded that sheriff’s officers had racially profiled Latinos. Snow has said the investigation was aimed at constructing a “bogus conspiracy theory” to discredit him.

Arpaio, who has launched investigations in the past of judges who were at odds with him, has vigorously insisted that he didn’t investigate Snow and instead said the probe was focused on widespread identity theft. In all, the sheriff’s office spent $250,000 on the investigation.

Prosecutors examining the overtime allegations tried to examine Mackiewicz’s cellphone to determine whether he was using it for personal or business purposes at the times in question.

The Attorney General’s Office said the cell provider wasn’t maintaining text messaging records at the time and that no information was available from his phone, which was restored to factory setting before Mackiewicz turned the phone into the sheriff’s office.

Prosecutors concluded there was no way to back up witness statements about Mackiewicz using the phone for personal business at the times in question.

“Prosecutors have an ethical duty to bring criminal charges only when there is a reasonable likelihood of conviction at trial,” said Mia Garcia, a spokeswoman for the Attorney General’s Office. “After reviewing the evidence submitted to our office, this case did not rise to that threshold.”

Requests to the sheriff’s office and Mackiewicz’s attorney for comment on the case weren’t immediately returned Wednesday afternoon.