The Securities and Exchange Commission on Wednesday sued the former head of a defunct Pittsburgh-area medical staffing company, claiming he led a stock fraud and misappropriated $6.4 million by lying about the company's finances.

The SEC sued Richard McDonald, who had already been charged by federal prosecutors, and three other former executives at World Health Alternatives Inc.

"A key aspect of the fraud involved the manipulation of World Health's accounting entries," the lawsuit reads. "This made the company appear more financially sound and masked McDonald's misappropriation of funds."

McDonald, 35, of Gilpin Township, was indicted in August in a wide-ranging fraud that federal prosecutors say has cost investors more than $200 million.

According to that 20-count grand jury indictment, McDonald allegedly diverted funds from World Health while president and chief executive officer from 2003 to 2005. McDonald is also accused of failing to pay some $2.3 million in federal taxes withheld from employee payroll checks and with evading his own federal taxes.

McDonald has an unlisted phone and his criminal defense attorney, William C. Kaczynski, said he doesn't represent McDonald in the SEC matter and doesn't know if anyone else does. Kaczynski relayed a request for comment to McDonald, who did not immediately respond Wednesday.