State authorities are probing what could be the most significant police corruption case in years in perpetually troubled Opa-locka.

According to city memos obtained by Miami New Times and confirmed by City Manager Clarance Patterson, officers have told internal investigators that city cops:

• had sex with arrested offenders "in lieu of moving forward to prosecution, eventually unarresting the individuals and discarding the police report";

Info Opa-locka Police

• stole property from the station;

• ordered lower-ranking officers to release arrested suspects and discard the reports, which would violate state law;

• improperly transported liquor in police vehicles for private parties;

• horsed around with Tasers on the job;

• slept on duty.

"If proven, this is serious business," Patterson says. "This wasn't something that happened yesterday. It has been happening over the course of years."

The allegations are the result of a monthlong internal investigation that Patterson says he ordered in January after hearing complaints. He says many of the issues predate his tenure as manager, which began 15 months ago.

The Florida Department of Law Enforcement (FDLE) has found similar problems in the past. Opa-locka is one of Miami-Dade County's poorest cities. It has a long history of political corruption and discord.

To complete the report, the city's personnel director and an assistant city manager interviewed 11 members of the city's executive staff and six cops.

They found exceedingly low morale and that officers' complaints had often gone unaddressed. The report's comments section even notes, "The department is built on deception." Many other comments refer to racially charged issues in the largely black department.

In March, Patterson suspended Opa-locka Police Chief Cheryl Cason, who had served since January 2010, claiming she had failed to report a minor accident involving a city-owned car. She returned to the job after several weeks, saying she had left a message on city voicemail noting the collision with a pole next to her driveway.

Patterson said he contacted the FDLE to report the findings and that agents — after contacting county prosecutors — had agreed last Thursday to probe the city's department.

Asked why no one has been fired, Patterson says, "It looks radical, but these claims need to be proven... This happened over a period of years, but there are allegations against officers who are still here."