Lawyers for Eric Rudolph say federal agents and not their client may have spread explosives traces from an abortion clinic bombing in Alabama to his North Carolina home.
The defense effort came at the end of a three-day hearing in which testimony showed Rudolph, while at large, told a North Carolina store owner the government was trying to frame him for the blast. The 1998 explosion in Birmingham killed a police officer and critically injured a nurse.
Prosecutors say eyewitnesses and explosives traces found in Rudolph's home link him to the Birmingham bombing.
Captured last year in North Carolina after more than five years on the loose, Rudolph has pleaded not guilty. The defense has challenged eyewitness accounts as unreliable, and in the hearing this week they attempted to show the evidence in his home is unreliable as well.
US Magistrate Judge T. Michael Putnam issued no immediate ruling.
Rudolph also is charged in the fatal Olympic park bombing in Atlanta in 1996 and two more bombings in Atlanta in 1997.