Washington(CNN) A Russian company accused of bankrolling a vast online campaign to influence the 2016 US election joined the attacks against special counsel Robert Mueller's investigation on Monday.

Concord Management and Consulting argues that Mueller's appointment as special counsel was unlawful and that he lacked the authority to charge the Russian company with conspiracy.

Former Trump campaign Chairman Paul Manafort, who is also staring down charges from Mueller, previously tried a similar tactic to dispose of allegations he faces. One federal judge dismissed Manafort's request to void Mueller's authority in that case, while another hasn't yet ruled.

Concord's 63-page argument against Mueller's work is a dense collection of case law and legal theory, testing the special counsel's powers against the US Constitution. If the challenge is broadly successful, it could cripple Mueller's entire operation -- not just this criminal case.

A large part of the company's argument alleges that because Mueller was a private attorney appointed to the special counsel position, he has illegally investigated and prosecuted cases. And the internal Justice Department regulation that allowed for Mueller's appointment isn't enough to empower him because Congress never passed a similar law, the filing says. Mueller has few constraints on his authority, Concord says.

"In the absence of valid and binding regulations, the special counsel is unfettered and unsupervised, and the appointment order certainly is no cure for that," the filing says.

Concord gives several reasons why Mueller shouldn't be able to prosecute it. The company claims Mueller was not appointed by the President nor confirmed by the Senate, and thus is acting outside the law. And the case against Concord, it claims, goes outside of Deputy Attorney General Rod Rosenstein's appointment order in May 2017.

Mueller's team has three weeks to respond.