Hunter Biden's lawyers argued that the "rabbit hole of lies" allegedly told by the indicted FBI informant have infected the investigation into the president's son, per a Tuesday court filing.

Why it matters: While this is a separate matter to the indictment Alexander Smirnov faces concerning President Biden and his son, the lawyers' response signals the FBI informant's claims will form a key part of Hunter Biden's defense against tax charges.

Separately, Hunter Biden's lawyers asked a judge to dismiss his tax charges indictment in a filing in California Tuesday, citing "due process violations based on outrageous government conduct."

What they're saying: "The Special Counsel charged Mr. Smirnov with lying and obstruction, but the more interesting part of this story is not that Mr. Smirnov lied," state Hunter Biden's lawyers in a motion filed in Delaware Tuesday.

• "It is more remarkable that beginning in July 2023, the Special Counsel's team would follow Mr. Smirnov down his rabbit hole of lies as long as it did," it adds.

Of note: Attorney's for Hunter Biden said federal prosecutors mistook a photo of sawdust in his electronics for cocaine.

• "Multiple sources have pointed out, and a review of discovery confirms, this is actually a photo of sawdust from an expert carpenter and it was sent to Mr. Biden, not vice versa," the lawyers said, per the filing.
• "The prosecution is flat out wrong."

The big picture: Attorney General Merrick Garland named the Trump-appointed U.S. Attorney for Delaware David Weiss special counsel to lead the investigation into Hunter Biden last August after a plea deal with the president's son collapsed.

• Hunter Biden last month pleaded not guilty to nine tax-related charges in a federal court in California.
• Last October, he pleaded not guilty in Delaware to three counts related to his alleged illegal possession of a firearm.

Meanwhile, Smirnov was charged last week by Weiss with felony false statement and obstruction crimes for providing allegedly false information about President Biden and Hunter Biden.

• A federal grand jury indicted 43-year-old Smirnov for allegedly falsely telling FBI agents in June 2020 that officials with the Ukrainian energy company Burisma paid the Bidens $5 million each in 2015 or 2016.

Go deeper: DOJ: FBI informant said Russian intelligence involved in Hunter Biden story

Editor's note: This article has been updated with details of Hunter Biden's lawyers' filing seeking to dismiss his tax charges and further context.