It's not exactly sisterly love with the Judd sisters, as Ashley Judd has come forward with the claim that her half-sister -- country music superstar Wynonna Judd -- used a GPS tracking device to spy on her!

According to The New York Daily News, Ashley made the discovery of the tracking device on her Cooper Mini. Her mechanic pointed it out to her, and she filed the police report in Tennessee. "[Ashley] believed Wynonna Judd placed the device on the vehicle," a police report stated. "Or [she] had someone else place the device on her vehicle." The police did some research, and discovered that the culprit was a private investigator who was contracted by the elder Judd sister to track her younger sister. The P.I. gave it to Wynonna, who then had her ex-husband Arch Kelley place it on Ashley's car.

According to E! News, the sisters -- who didn't always have an adversarial relationship -- are currently feuding over an ongoing custody battle raging between them, and this latest discovery is the latest round of artillery fired. In an emotional interview last year, Ashley opened up about their rocky relationship, saying, "I absolutely know that my parents love and adore me, and I'm so grateful that today we have good relationships."

Later, as well, Ashley regretted opening herself and her family up to scrutiny, especially after her 2010 autobiography Olympus Has Fallen revealed that she had been the victim of sexual abuse. "We've learned that it's really best not to dissemble our relationships in public," she said. "We do to a certain extent but the details are really none of anyone's business."

Nothing like family unity to bring on the Christmas spirit, eh? The next time your parents complain that you should get along better with your siblings, mention that it could always be worse, and point them to the Judd sisters.