Most MKUltra records were destroyed in 1973 by order of CIA director Richard Helms .
It has been difficult for investigators to gain a complete understanding of more than 150 funded research sub-projects sponsored by MKUltra and related CIA programs .
Most MKUltra records were destroyed in 1973 by order of CIA director Richard Helms , so it has been difficult for investigators to gain a complete understanding of more than 150 funded research sub-projects sponsored by MKUltra and related CIA programs .