A nine-year-old Michigan boy allegedly shot and killed his adoptive mother with a rifle at their home Monday.

Police said 51-year-old Pauline Randol was shot dead inside her Fawn River Township home. The victim’s family said the body was found in the living room.

Harley Martin, the boy's adoptive sister, said, "I want people to know that he's not a bad kid. He loved his mom. I don't want people to think he did not love his mom."

Martin said Randol adopted the boy in 2016. She added that the boy, whose name was not revealed, had a troubled past as his biological mother used drugs during her pregnancy. Martin said the boy had mental issues.

"He had a lot of mental issues that were not getting helped. He started on medication last week. Who knows how that reacted?" she said.

Martin said Randol had expressed concerns about the boy's mental health issues.

"She had told her doctor one time she was so scared she was raising the next serial killer," Martin said, adding that nobody, however, expected the boy to hurt his mother, NBC-affiliated television station WOOD TV reported.

Speaking to Fox 17, Joseph Lancaster, a neighbor, said he knew the boy and that he had previously shot at his grandchildren with a BB gun.

“My wife and I both, when we heard that the woman was shot, we both looked at each other and said ‘I bet it was him.’ The little boy, because I have grandkids. I have one the same age and I’ve got smaller ones. And he would stand in the tree line over there and point his BB gun at him and shoot at them.” he said.

Calling her mother an “amazing woman,” Martin said, “She would do it all over again if she had to, and that’s the messed up part. I know she’s at peace. I know she still loves him and I know she would not want people thinking bad of him."

The boy was charged with open murder and felony firearms charges. He was sent for a psychiatric evaluation at a state-run juvenile facility. During his preliminary hearing Tuesday, the boy reportedly asked where his mother was.

Crime Scene Michigan
In this photo, a crime scene tape is seen marking off a site in Roseville, Michigan, Sept. 27, 2012. Getty Images/Bill Pugliano

T.J. Reed, the attorney representing the boy, said, “At this time, I am unable to comment on the facts or status of the case. It is important to allow this case to properly move through the legal process and to non pre-judge this child based on partials or unknown facts. The child still retains his presumption of innocence and is entitled to privacy during this process and I would ask that the child and the family be given that privacy.”

The boy was a second-grader at Congress Elementary School in Sturgis. He threatened to stab an eight-year-old schoolmate in 2018.

“He told her that he wanted to get a knife and stab her and watch her die, and watch her mother cry,” Alecia Pieronski, the girl's mother said, adding, “My want was to remove him from the school and protect the children. I do feel in my whole heart the teachers and principals did everything they could do," CBS-affiliated television station WWMT reported.

In a statement Wednesday, Art Ebert, Sturgis Public Schools superintendent, said, "Our community has experienced a tragic event. As a district, it is our goal to provide support to our students, staff and the community. We are limited in what we can share due to privacy laws and the sensitive nature of this tragedy. The St. Joseph County Sheriff's Department is leading the investigation regarding this event that occurred outside of school, including the release of information about the investigation.”