NASHUA, N.H. – A man who pleaded guilty to hiding evidence and concocting an alibi for those charged with killing a mother during an October home invasion said Friday he is bipolar and was being treated for depression until last year.

Autumn Savoy, 20, entered pleas Friday to hindering prosecution and conspiracy in exchange for a recommended sentence of 5 to 19 years in prison. He has agreed to testify for the state.

Savoy, of Hollis, is the last of the five defendants to enter pleas this week. The three defendants charged with first-degree murder and other felony charges — Steven Spader and Christopher Gribble of Brookline and William Marks of Amherst — entered pleas of “not guilty” in court documents and waived their court appearances.

Quinn Glover, of Amherst, who has also struck a plea bargain with prosecutors in exchange for his cooperation, pleaded guilty Monday to felony charges of robbery, burglary and conspiracy.

Glover was inside the Mont Vernon house in the early morning hours of Oct. 4 when Kimberly Cates was hacked to death and her 11-year-old daughter, Jaimie, was severely injured. But Senior Assistant Attorney General Jeffery Strelzin said he did not participate in the attacks. Glover agreed to a sentence of 20 to 40 years for his role in the home invasion.

Savoy and Glover will not be sentenced until after the prosecutions of the other three defendants are finished.

Savoy is charged with helping Spader and Gribble throw evidence into the Nashua River and telling investigators the pair spent the night of the killing at his home. Strelzin told Superior Court Chief Justice Robert Lynn on Friday that Spader and Gribble told Savoy of their plans to break into the home the day before, and after the crime told him they had killed two females at the house. The pair did not know at that time that Jaimie Cates had survived.

Savoy admitted in court that Spader and Gribble came to his house after the attacks and asked him to burn a bag containing the shoes and clothing the four men had worn during the attack, a machete and knife used in the attack and items taken from the Cates’ home. Savoy declined to burn the items, Strelzin said, and instead accompanied the pair to the river where they threw the bag in.