UPDATE: The SEC has accused investors in three companies with stock manipulation after running a sting with an unnamed "cooperating witness" in Philadelphia. Acting U.S. Attorney Laurie Magid opened three indictments and an "information" alleging conspiracy and securities fraud against seven people in relation to the investigation. Read the SEC press release here; scroll down for links to civil complaints.

  EARLIER: Movie and video investor National Lampoon Inc., Los Angeles (NYSE Alternext: NLN), and electrical-therapy developer Advatech Corp., West Palm Beach (ADVA), were suspended from trading over the next two weeks by the Securities and Exchange Commission, which cited "a lack of current and accurate information concerning the securities" in an order from SEC acting secretary Florence Harmon.

UPDATE: Both companies and some of their investors were accused of stock manipulation today by the SEC. Investors in a third, non-public company, Swedish Vegas Inc., were also accused.

  NJ ANGLE: National Lampoon's largest outside investor is the New Jersey Division of Investments, which manages state workers' and teachers' pensions, and which held 270,000 shares after selling 30,000 during the second quarter, according to a database maintained by Bloomberg LP from public records. The stock has been selling below $1 a share. No immediate comment from New Jersey spokesman Tom Vincz.