Bogdan Ivanovich Krilov is a member of The Blacklist.
Background
Bogdan Krilov was a medical doctor that had mastered the art of memory manipulation, being able to implant false memories in his victims, change their memories, or erase his victim's memory. Krilov sold his services to the black market and was hired to erase the memories of witnesses, destroying the prosecution's case. Krilov erased Elizabeth Keen's memories about the night of the fire.
Season 4
"Dr. Bogdan Krilov"
"The Debt Collector"
Harold Cooper mentions that Krilov has agreed to testify.