New details are revealed in a court filing this week in the case against Dr. Randeep Mann, a Russellville physician who's been indicted in the February 2009 blast that hurt Dr. Trent Pierce. Prosecutors have said Mann planned the attack to retaliate against the state medical board's disciplinary actions against him.
An affidavit filed by prosecutors says investigators believe the bomber used a military grenade and a vehicle tire and rim to make a homemade bomb.
Mann has pleaded not guilty to the bombing and also faces charges of illegally possessing grenades.
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