JUNEAU, Wis. (AP) _ The trial of a 20-year-old state legislator's son accused of killing his mother with a hunting arrow was recessed Saturday by a visibly angry judge responding to a defense motion for a mistrial.

Defense attorney Henri Conti asked for a mistrial after state Rep. Robert Goetsch testified about a two-foot pipe weapon found at the scene of his wife's death.

Conti said District Attorney Kevin Schram had not previously disclosed information about the pipe.

''It was withheld and dropped on us today,'' Conti said. ''It's substantially prejudicial. It's poisoned the well. It's grounds for a mistrial.''

Court rules require the prosecution to disclose evidence and testimony that is expected on the stand so the defense can adequately prepare its case.

Goetsch's son, Chad, is charged with first-degree intentional homicide for fatally shooting 51-year-old Carolyn Goetsch in the heart with the arrow on Nov. 8.

Chad also is charged with recklessly endangering safety for pointing a second arrow at his father and fighting with him after Mrs. Goetsch was shot.

Dodge County Circuit Judge Daniel Klossner said he would consider the motion for a mistrial unless prosecution and defense lawyers can come to an agreement that would allow ''curative'' instructions to the jury.

Klossner said he would rule on the mistrial motion Monday after considering the attorneys' proposed jury instructions.

Goetsch described the circumstances surrounding his wife's death at the family's home in the town of Oak Grove.

Conti made the motion for a mistrial after Goetsch testified his son made the pipe weapon last fall to protect himself after being attacked and robbed.

Schram said he learned about the pipe while talking informally to Robert Goetsch on Aug. 22. He said the conversation does not fall under the rules of evidence and did not need to be revealed to the defense.

In other testimony, Goetsch said his son threatened Mrs. Goetsch so often last summer and fall that she talked about buying a gun because she was afraid her son would kill her.

''I guess she did take them (the threats) more seriously than I,'' Goetsch said. ''We talked about buying a gun. She started insisting on locking the doors. She said she was afraid of him. She was afraid he was going to kill her.''

The day his wife died, Goetsch said his wife got out of bed early in the morning after both heard a knock on the door. Goetsch said he heard his wife's voice and another voice, but went back to sleep until he was awakened by loud screaming.

His wife appeared in the doorway of their bedroom and collapsed, he said. When he went to the body, he said, he saw his son standing in the hallway aiming a loaded hunting bow at him.

Goetsch said he lunged over the body and grabbed the arrow pointed at him and broke it. He said he and Chad then fought for several minutes throughout the house while his daughter Shana, then 14, tried to call police.

Chad broke away at least once and attacked his sister while she called authorities, Goetsch said.

Goetsch said he asked his son, who was supposed to be away at college: ''Why did you kill my wife ... Why are you here?''

He said his son replied: ''I was lonesome.''