When police arrived, they discovered the victim's body inside the Camilleris' home, according to 9News. A 4-year-old boy, believed to be Camilleri's nephew and the victim's grandson, also had minor injuries and was taken to a nearby hospital, the Australian Associated Press reported.
Police arrested Camilleri, who told a judge via video Sunday that she is mentally ill and needs medical treatment, the Morning Herald reported.
She added that she couldn't move her fingers after the attack.
"I couldn't even wash myself properly when I had to shower to get all the blood off," she said, according to the Morning Herald.
Camilleri likely will undergo a mental health evaluation, police said.
Her nephew is "being cared for by his family," police told 7News.