The U.S. Attorney's Office in Philadelphia says a doctor submitted false claims to trust funds that were put into place for people harmed by Fen-Phen, a prescription weight-loss drug. The doctor has been charged with signing forms certifying patients who took the drug suffered from heart damage when they didn't. Mail fraud charges are "darlings of the prosecutors' arsenal," said Edward Ohlbaum, a professor at Temple's Beasley School of Law. "Virtually any use of the mail…satisfies the statute's mailing requirements with regard to almost any type of fraud."