8:33 PM PT -- Mark S. Zaid, the attorney for RR, tells us, "We have been attempting to work with the Petty family for weeks to verify the lawful title of the late Tom Petty's items. As a reputable auction house for half-a-century, we obviously can't simply accept blanket statements of theft without presentation of even the slightest proof. We have asked numerous questions of the Petty family and received few answers. Despite our ongoing investigative efforts, the Petty family has gone radio silent since May 30th. It seems every new detail - such as the claim a police report has been filed - we unprofessionally learn of through the media. Although we have not heard from the police, we welcome cooperation from law enforcement authorities. RR Auction takes these matters incredibly seriously, which is why we withdrew the consigned items from auction until proper ownership can be determined."
Tom Petty's family has cops taking a closer look at his wardrobe, at least the items that ended up on an auction block ... and we've learned it's a grand theft investigation.
Law enforcement tells TMZ ... the late singer's family members filed the report last week after discovering Tom's belongings were up for auction. They're pissed because, according to them, the items were last seen getting loaded into an L.A. storage unit.
We're told LAPD took a grand theft report and will now investigate the matter.
TMZ broke the story ... Tom's jackets, shoes, hats and clothes showed up in an RR Auction lot last month ... but then the family called foul, claiming Tom's gear was actually stolen.
The auction house says Tom's stuff was consigned by a third party to be auctioned starting June 22 ... and they say the gear is from Tom's former home in Encino, CA.
After Tom's family raised concerns, RR Auction pulled the items and told us they were "aggressively investigating the situation."
We reached out to the auction house regarding the new police report ... so far no word back.
As the man himself once sang, the waiting is the hardest part!
Stay tuned ...