New York ? After months of secretly working with the FBI, Bernard Madoff’s right-hand man emerged in federal court on Tuesday and pleaded guilty to conspiracy and other charges, contradicting claims by the disgraced financier that he acted alone.

“I was loyal to him. I ended up being loyal to a terrible, terrible fault,” Frank DiPascali told a judge during a hearing at which his long-rumored cooperation deal with the government was confirmed.

Both prosecutors and defense attorneys portrayed DiPascali as the man who could unlock his former boss’ epic Ponzi scheme and potentially make cases against other defendants.