Atlantic City's Revel casino, which announced earlier this month that it will soon shutter, lost more than $20,000 in cash when the money fell off the roof of an armored truck, according to a report from The Press of Atlantic City.
An investigation is underway after Boston-based GardaWorld armored car services told the casino on Aug. 6 that it had lost $21,000, the newspaper said, citing an incident report.
Read More Revel Casino says closure will help it find a buyer
The report said the cash was left on the roof, and that surveillance video from another casino shows the bag still on the vehicle during a subsequent pickup. The news article said that it "is not clear where or when the money fell off."
Read MoreAtlantic City's Revel Casino to close in September
"We are cooperating with the authorities in investigating this incident and cannot provide any additional details," Joe Gavaghan, GardaWorld director of corporate communications, told The Press of Atlantic City.
Revel spokeswoman Lisa Johnson said she couldn't comment on the case, the newspaper's report said.
—By CNBC.com staff