The Wall Street Journal is reporting that the government’s investigation into insider-trading is being built on information from five cooperating witnesses, some of whom received information from investors and companies that haven’t been originally charged in the probe, potentially broadening the case.

The complaint released Thursday named two additional cooperating witnesses in the government’s insider-trading case against Raj Rajaratnam, founder of hedge fund Galleon Group: Steven Fortuna, of Boston hedge fund S2, and Gautham Shankar, a proprietary trader at Shottenfeld. Mr. Rajaratnam has denied wrongdoing. The men, join three others — Roomy Khan, Ali Far and Richard Choo-Beng Lee — who were previously identified as cooperating witnesses in the case and have admitted to engaging in illegal insider trading for many years. The cooperators have pleaded guilty to charges including conspiracy and insider trading and are cooperating in the hope of getting lighter penalties, investigators say.

Mr. Lee’s Cooperation Agreement suggests that he engaged in illegal insider trading while working at Steven Cohen’s SAC Capital, the Connecticut-based hedge fund. Coincidentally, Mr. Cohen is said to be “out of the country” until Monday in the midst of all of this.  Stay tuned …