At the RSA Conference on Thursday Ronald Plesco, counsel to the National Cyber-Forensics and Training Alliance, a computer forensics organization established by the FBI and private industry, pointed to the trend in recent years of spammers building networks of compromised computers to launder their fraudulent e-mail offerings. Tim Rosenberg, a research professor at the George Washington University, warned of “multinational groups of hackers backed by organized crime” and showing the sophistication of prohibition-era mobsters…