Authorities have seized a 45-ton Panther tank, a flak canon and multiple other World War II-era military weapons in a raid on a 78-year-old collector's storage facility in northern Germany.

Kiel prosecutor Birgit Hess said the collector is being investigated for possibly violating German weapons laws but his attorney Peter Gramsch told the dpa news agency all the items were properly demilitarized and registered.

The collector, whose name wasn't released, made no secret of his collection, even bringing the tank out during a bad winter to plow neighbors' snow, newspaper Kieler Nachrichten reported Friday.

He came to authorities' attention in an investigation into black market Nazi-era art that turned up two bronze horse statues that once stood in front of Adolf Hitler's chancellery. Those were in another man's possession.