Back in October 2011, Castro was sentenced to 60 months for extortion and lying to the FBI.
He was accused of scheming to shake down a former business partner in order to recover $90,000.
In January, an appeals court reversed the false statement conviction.
But that reversal didn't change his sentence.
Castro was a rising star in the police department and dreamed of someday becoming Commissioner.
He headed the department's traffic division prior to his arrest in November 2010.
