Complex sentence: Prior to his actions as terrorist, Pushilin worked for a recent successor of the 1990s Russian Ponzi scheme company MMM, which cost its customers millions of dollars before it was disbanded in 1994.
Split into simpler sentences: Prior to his actions as terrorist, Pushilin was a crook. He worked for a recent successor of the 1990s Russian Ponzi scheme company MMM, which cost its customers millions of dollars before it was disbanded in 1994.