A son-in-law of former New York state Assembly Speaker Sheldon Silver has admitted cheating investors out of nearly $6 million in a Ponzi scheme.

Marcello Trebitsch (mar-SEL'-oh TREH'-bich) pleaded guilty Monday to a securities fraud charge in Manhattan federal court.

Sentencing is scheduled for Nov. 2. A plea agreement calls for four to five years in prison.

Defense attorney Benjamin Brafman says he'll seek leniency for Trebitsch. He says Trebitsch was a good man who got in over his head when dealing with a sophisticated investor.

Trebitsch says he carried out the scheme from 2007 until last year. He has apologized.

Trebitsch is married to Silver's daughter. His plea comes as Silver faces unrelated corruption charges in the same court.

Prosecutors say Silver took nearly $4 million in payoffs and kickbacks. The Democrat says he'll be vindicated.