An expert on Russian intelligence was critically injured in a shooting in front of his suburban Washington home, authorities said.
Joyal was shot Thursday by two men in his driveway, police said.
The shooting appeared to be a random robbery and street shooting, a law enforcement official with knowledge of the case told The Associated Press. The official spoke on the condition of anonymity because the person did not have authority to comment on the case.
In an interview broadcast last Sunday on "Dateline NBC," Joyal also accused the Russian government of trying to silence its critics.
"A message has been communicated to anyone who wants to speak out against the Kremlin: If you do, no matter who you are, where you are, we will find you, and we will silence you — in the most horrible way possible," Joyal said.
Russian President Vladimir Putin and Russian officials have repeatedly denied involvement in the Litvinenko case.
Joyal and Litvinenko were acquaintances, said Oleg Kalugin, a former KGB counterintelligence chief who is now a U.S. citizen and who met with Joyal several hours before he was shot.
Kalugin also said Joyal's condition was improving.
Joyal works for National Strategies, a Washington-based government consulting firm.