One defendant charged in 2012 Manchester double homicide will plead guilty Tuesday

A 20-year-old charged with first-degree murder in a 2012 double homicide of his friend's grandparents will plead guilty to a lesser charge Tuesday in Delaware County District Court.

Brandon Ahlers of Manchester is charged with two counts of aiding and abetting in first-degree murder for his part in the slaying of Janet Sweet, 62, and Richard Sweet, 55, of Manchester, May 13, 2012. He is accused of suggesting to his friend, Isaiah Sweet, different ways to kill the couple.

Delaware County Attorney John Bernau wasn't available for comment on the plea agreement Monday. He was in a hearing in Des Moines.

Ahlers' plea will be 1 p.m. Tuesday.

Isaiah Sweet, 18, of Manchester, is also charged with two counts of first-degree murder in the homicide. He is accused of shooting and killing his grandparents. The couple was found dead in their home May 13, with gunshot wounds to the head. Relatives found the bodies when they came over for Mother's Day.

According to an affidavit for a search warrant, Ahlers admitted to investigators that Sweet had asked him to come over to discuss killing the couple. Ahlers said he suggested options including poisoning, drugging and shooting them, but he cautioned Isaiah not to use an assault rifle in the house because "everyone" could hear the gunshots.

Ahlers also helped Sweet get rid of the rifle used in the killing, according to the search warrant.Isaiah Sweet's trial is set Oct. 16, and he has asked for a change of venue.