An anti-abortion activist says he's the one who killed a Kansas abortion provider — and did it because it was necessary to save lives. But one of his attorneys says there's no such thing as a "necessity defense" in state law, and that is not the strategy the defense team plans to present at his trial.

Scott Roeder told The Associated Press in a telephone call from jail on Monday that he plans to argue at his trial that he was justified in shooting Dr. George Tiller to protect unborn children.

"We have explored that possibility," public defender Steve Osburn said a day after his client's confession. "That does not seem to be the approach that is viable, nor is it the approach we intend to use."

Roeder, 51, of Kansas City, Mo., is charged with one count of first-degree murder in Tiller's death and two counts of aggravated assault for allegedly threatening two ushers who tried to stop him during the May 31 melee in the foyer of the doctor's Wichita church. Roeder has pleaded not guilty and is scheduled to go to trial in January.