A judge has questioned the viability of a prosecution against a man accused of illegally building hundreds of untraceable rifle silencers under what had been a secret contract with the Navy Seals.

At a pretrial hearing Friday, Judge Leonie Brinkema suggested that there may be classified evidence in the case that shows California race-car mechanic Mark Landersman had legitimate — but off-the-books — authorization to build the silencers from the Navy. If so, she said, she doubted that prosecutors could win their case.

Prosecutors Friday disagreed with Brinkema's assessment of the case.

Landersman's lawyers maintained that his actions were lawful and authorized.

Court records indicate that Landersman was paid $1.7 million in 2012 to build 349 suppressors.