The order appears to be the latest effort by the Russian government to silence the imprisoned Alexei Navalny.
Mistaking Navalny's name as "Navatny," Don Jr. equated Putin poisoning him with a nerve agent to the legal woes of his dad's business.
"In the end, not much was accomplished, but no damage was done," Christie said. "That's probably all they were looking for ... to come out unscathed."
The Russian leader downplayed the Kremlin's crackdown on dissent and got philosophical at times.
"He will not be treated any worse than anybody else. Nobody should be given any kind of special treatment," Putin said of Navalny, his top critic.
President Biden has called the Russian president a killer, while former President Trump largely stayed silent on the Kremlin's alleged assassinations.
Navalny's chief of staff visited Washington, DC, ahead of Biden's highly anticipated summit with Putin in Geneva on June 16.
"If there aren't clear deliverables ... criticism will grow that this high-level meeting ultimately benefited the Kremlin," a former US official said.
The move sends a clear message to Biden that his criticism of Russia over the treatment of Navalny will not derail Putin's war on dissent.
Amid growing backlash at home, Russian President Vladimir Putin is sending a muscular message abroad.
Alexander Murakhovsky, who treated Navalny last year, had left a hunting base on an all-terrain vehicle before he went missing on Friday.
Daria Komarova documented the pro-Navalny demonstrations while on assignment for a local outlet that's funded by the US Congress.
Taken together, these moves represent a remarkable crackdown on dissent by Russian President Vladimir Putin.
The imprisoned Russian opposition leader's defiant comments came during his first public appearance after a weeks-long hunger strike.
The Russian opposition leader appeared in court via video link from jail on Thursday. He ended a 23-day hunger strike earlier this month.
Russian President Vladimir Putin's chief domestic critic made the announcement Friday on Instagram. He had been on a hunger strike since March 31.
Kremlin critic Navalny has been on a hunger strike since March 31, and has been denied access to doctors.