10/31/2008 at 04:00 PM EDT
Country singer Mindy McCready has been released from a Tennessee jail after serving half of a 60-day sentence for violating probation on a 2004 drug charge.
The platinum recording artist was released at 9 a.m. Friday morning, said Williamson County Sheriff’s Lt. Mark Wainwright, who added that it's not unusual for a well-behaved inmate to serve only half of a sentence on a probation violation
"Good behavior, a system that credits two days for each day served, and her job as a pod janitor here – all of that reduced her sentence," Wainwright tells PEOPLE.
McCready, 32, was accused in June of falsifying her community service records and violating probation imposed in 2004 for fraudulently obtaining prescription painkillers.
In July 2007, the troubled singer served five months after a scuffle with her mother, and resisting arrest, at her mother's home in Fort Myers, Fla.