A former McKinsey & Co partner whose devastating testimony helped convict Galleon Group founder Raj Rajaratnam and former Goldman Sachs Group Inc director Rajat Gupta of insider trading was sentenced on Thursday to two years probation. Anil Kumar, 53, was arrested on the same day in 2009 as Rajaratnam, his friend of 25 years. But instead of fighting charges that he leaked stock tips to the Galleon Group founder, Kumar immediately became one of the U.S. government's most valuable assets in its wide-ranging probe of illicit trading on Wall Street. Kumar committed "quintessentially dishonest criminal conduct," Judge Denny Chin said at Thursday's sentencing in Manhattan federal court. Yet, Kumar's assistance to the government, charity and contrition warranted a break from prison, the judge said.