NASHUA, N.H. — A co-defendant charged in a home invasion attack that left a woman dead and her daughter maimed testified Tuesday that Steven Spader wielded a machete in both hands as he struck the victims.

William Marks, 19, of Amherst said Kimberly Cates and her 11-year-old daughter Jaimie pleaded with their assailants before Spader brought the machete down on them as they huddled in bed.

Marks said he heard the daughter cry, “Please. You don’t have to do this.” He said he heard Kimberly Cates trying to reassure Jaimie Cates that everything would be all right.

Spader “started hitting them with the machete,” Marks said. “It sounded like a baseball bat hitting the mattress.”

Spader’s trial is in its second week. He and four others have been charged in the case. Marks previously agreed to plead guilty to conspiracy to commit murder and burglary and accomplice to first-degree assault in exchange for a 30-60 year sentence.

In testimony Tuesday, Marks said that although the intruders cut the power to the house, he could see the attacks by the light of a full moon.

Spader, 18, of Brookline, stared stone-faced at Marks throughout the testimony. Aside from his initial identification of Spader, Marks faced the jury and did not look back at Spader.

On cross-examination, Marks admitted he and his father talked about selling his story to a national television network to make money just weeks after he was taken into custody. He also said he initially lied to police to protect himself and his friends.

Marks repeatedly maintained he did not take part in the attacks. He said that Spader and co-defendant Christopher Gribble, who is scheduled to go on trial in February, dealt all the blows.

Marks said he saw Jaimie get thrown against a wall. As she lay bloody and crumpled on the floor, Spader whacked her in the head with the machete and kicked her, Marks said. He said Gribble told him he had slit Kimberly Cates’ throat.

When asked by prosecutor Jeffery Strelzin if he tried to stop the attacks, Marks replied,”No.”

Marks said Spader told him later that day he had wiped the machete down with ammonia and bleach. Investigators say they found the weapons buried in a wooded area of Brookline.

After the graphic testimony and during a court break, a cameraman said a man asked him to stand guard outside the men’s room door because David Cates, Kimberly’s husband and Jaimie’s father, was breaking down inside the bathroom. He was traveling on business when his wife was killed.