Actor James Caan has sent a letter of thanks to Brooklyn District Attorney CHARLES HYNES for launching an investigation into allegedly corrupt FBI agent LINDLEY DeVECCHIO. THE GODFATHER star's friend JOSEPH (JO-JO) RUSSO was jailed in 1992 for murder and racketeering after an investigation by DeVecchio, and Caan is convinced of his innocence and is thrilled the case has been reopened. According to the New York Daily News, he wrote: "To thank (Hynes)... for undertaking such an extensive and malignant corruption case. "Joseph Russo is a dear friend of mine and I cannot express enough how pleased I am that your office has taken interest and is in pursuit of correcting this problem, (and) taking the time to evaluate the situation to correct the wrongs that have affected so many lives." DeVecchio is also suspected of helping mobster GREGORY SCARPA kill 17-year-old drug-dealer and alleged informant PATRICK PORCO in 1990. Porco's family lawyer DAVID SCHOEN says, "Losing Patrick Porco as a teenager ruined the lives of his entire family. "The family is stunned now to learn that an FBI agent is allegedly involved in Patrick's murder. Stunned, and they're looking forward to getting to the bottom of what happened." Former New York Police Department detective JOSEPH SIMONE is also pleased at the news of DeVecchio's indictment, claiming the agent ruined his life by accusing him of leaking information to the mafia during the 1992 Colombo wars. Simone was later acquitted but lost his job in 1996 for failing to report bribe attempts and receives no pension despite 20 years on the force. He says, "I hope now that the real rat is getting indicted, maybe that will allow the department to reconsider my case."