Simplify the following text for a Grade 8 native English-speaking person.
Original: Lavrentiy Beria , the head of the secret police organization NKVD ( the predecessor of the KGB ) , used the Buran device to spy on the U.S. , British , and French embassies in Moscow .
Simplified: Lavrentiy Beria , head of the KGB then used Buran to spy on US , British and French embassies .