A New York lawyer disbarred after he pleaded guilty to insider trading charges testified Thursday that envy of Wall Street salaries led him to a role in what became the biggest hedge fund insider trading case in history.

Brien Santarlas was the first major government witness to testify at the second trial that resulted from the investigation that ended in more than two dozen arrests and the conviction last week of Sri Lankan-born Raj Rajaratnam, a one-time billionaire hedge fund founder who became one of America’s richest men.