Lester Crawford, the former Commissioner of the US Food and Drug Administration who stepped down unexpectedly from the post last year, is the subject of a criminal investigation by a federal grand jury over allegations of financial improprieties and false statements to Congress.

The investigation seems to centre on financial holdings in pharmaceutical companies held by Crawford and his wife in and before 2004, when he was serving as acting FDA Commissioner, before being confirmed in the position in July 2005. He resigned from the post last September, saying the FDA needed fresh leadership. The Department of Health and Human Services launched a probe into the reasons for his departure the following month.

The criminal investigation was disclosed during a hearing on procedural matters in a civil suit filed against the FDA over its handling of the emergency contraceptive Plan B, according to a Wall Street Journal report.

Debate over the FDA's alleged reluctance to approve Plan B dragged out Crawford's nomination process. The file for the morning-after pill has languished at the agency for two years, drawing accusations that the Bush Administration has pressured the agency to shelve it on ideological grounds.