< Russian oppositionist Vladimir Kara-Murza, Jr. (file photo)
By Carl Schreck and Mike Eckel for RFE/RL:
The wife of well-known Kremlin critic Vladimir Kara-Murza, Jr., who fell critically ill last week in Moscow for the second time in two years, said doctors have diagnosed him with "acute poisoning by an undetermined substance."
Yevgeniya Kara-Murza told RFE/RL on February 6 that samples of her husband's blood, hair, and fingernails have been sent to a private laboratory in Israel in an effort to identify the toxin that triggered his sudden illness.
"We want to get some samples tested again to try to determine what this 'unidentified' substance may be," she told RFE/RL in a Facebook message.
Doctors at the Moscow hospital where Kara-Murza is being treated could not immediately be reached for comment.
Kara-Murza, 35, was hospitalized on February 2 and placed in an intensive-care unit. His wife said later that her husband had suffered kidney failure and was on life support after being placed in a medically-induced coma.
She said he was still in a coma on February 6 but his condition had stabilized.
His friends and family say his symptoms closely resemble those he suffered in May 2015, when he abruptly fell ill in Moscow and was hospitalized in critical condition.