It was to be a South Florida racketeering case of massive proportions.

A major private security firm billed Miami-Dade County millions of dollars for security services it did not provide on its Metrorail stations, prosecutors alleged. In all, eight ex-or-current Wackenhut employees were charged in an overbilling case believed to have cost taxpayers more than $3 million.

But two years later, the case has fizzled.

Most of the defendants got probation. Charges were dropped against two high-level executives. And a judge threw out the charges against another defendant.

And in the final case, former Wackenhut supervisor Elijah Pendleton, 69, late last month agreed to a sentence of five years probation, plus 150 hours of community service.

State prosecutors dropped the racketeering charge against Pendleton, who supervised Wackenhut’s Metrorail contract, after a key witness recanted during a deposition.

As part of a civil settlement, Wackenhut paid the county $3 million.

Wackenhut, which began guarding Metrorail stations in 1989, has changed its name and to G4S Secure Solutions – and it is seeking new county contracts. The firm was among several selected to provide security at the Port of Miami and for two Miami-Dade homeowners’ associations last year.

“We are relieved that this is behind us and that the company wasn’t charged,” a G4S spokeswoman said last week. “We believe the company’s honesty and integrity has been recognized to be intact.”

Miami-Dade prosecutors said Wackenhut employees stole at least $76,000 in 3,500 hours of security work not performed between 2002 and 2005.

Employees conspired to bill the county for “ghost posts” — security shifts never filled, or only partially filled, prosecutors said.

The total amount fraudulently billed to the county is likely much more, investigators said, because a 2008 county audit estimated overbilling at $3 million to $5 million.

Wackenhut long insisted the audit was flawed.

The company has been under scrutiny since 2005 when former employees filed a series of lawsuits alleging that the company could not cover its shifts, forcing supervisors and roving patrols to fill the gaps.

After the allegations surfaced, the county stopped doing business with the Palm Beach Gardens-based company.

In September 2010, Miami-Dade police arrested Pendleton, Nathan Holmes, Robert Alvarado, William Acosta and Roberto Pereira. Each pleaded guilty to grand theft, agreed to five years probation and to cooperate against Pendleton and higher-level employees.

A secretary, Erika Reyan, and two higher-level executives, Rene Pedrayes and Eduardo Esquivel, were charged later that month.

But witness problems plagued the prosecution’s case.

One key witness, Juan Leonardo Aviles, a former Wackenhut security captain who was not charged, was to provide strong testimony in the case, but he was gunned down in May 2011 while visiting family in Puerto Rico.

Aviles, who had become a Miami-Dade police officer, worked with Wackenhut for several years and testified about unmanned “ghost posts” billed to Miami-Dade County.

He told investigators he took his concerns about the ghost posts to Pendleton in 2002, but Pendleton “told him that he did not need worry about that,” according to an arrest warrant.