Updated

The Pentagon (search) is investigating eight additional Air Force (search) contracts to determine whether they were manipulated or influenced illegally by Darleen Druyun, a former Air Force official who was convicted last year of giving Boeing Co. (search) special treatment on a tanker lease deal.

The eight contracts range in value from $42 million to $1.5 billion and their total value is about $3 billion, according to a summary provided by the Pentagon on Monday.

Michael Wynne, the acting chief of Pentagon acquisition programs, told reporters that the eight contracts were identified as suspicious from among 407 reviewed by a team of military and civilian contracting experts. They referred the eight to the Pentagon's inspector general.

The eight are in addition to seven others that already are being investigated.

Wynne stressed that it is not yet clear that any of the additional eight have been tainted. They were picked for further investigation because they "seemed to be out of the normal process."

The review and investigations are an outgrowth of revelations about Druyun's handling of the multibillion-dollar deal with Boeing that would have allowed the Air Force to lease a fleet of new aerial refueling aircraft. Congress eventually killed the deal because of Druyun's involvement.

Druyun was an Air Force acquisition executive who later was hired by Boeing as a top executive. Last fall she pleaded guilty on felony charges and was sentenced to nine months in prison.

Boeing's former chief financial officer, Michael Sears, has also pleaded guilty for his role in hiring Druyun.

The eight contracts that were referred for further investigation were awarded between 1998 and 2002, Wynne said. The contractors involved are Boeing, Lockheed Martin (search), Andersen Consulting (search), Systems & Electronics Inc. (search), and Pemco (search). The biggest was a $1.5 billion award to a Boeing-Pemco team in 2000-01 for depot maintenance for the Air Force's KC-135 aerial refueling aircraft (search).

Wynne said the reviews and investigations have not identified any other Air Force acquisition executive, besides Druyun, who acted improperly or illegally in the contracting process.