According to an affidavit released Monday by the Collin County Clerk's Office, the grandmother of the 6-year-old dubbed "Wylie's Angel" abandoned the child in a park with a note indicating he had medical needs.
Gerren Isgrigg's body was found in a pile of brush near the shore of Lake Lavon on April 15 by a landscaper. According to the affidavit, the boy's grandmother, Darlene Phillips, had left the blind and deaf child at the park on April 12.
She said she left a note with the child saying, "I'm 6, I have seizures, I need medication and a feeding tube." Investigators have not located the note.
Phillips was arraigned Monday on a charge of murder. She said very little during her arraignment and denied a request for a interview from the Collin County jail.
In an interview Friday with the Allen Police Department, Phillips admitted to removing the child's feeding tube prior to leaving him at the park. Phillips said that she felt like she was being punished by her daughter, Nyki Phillips, by having to care for her child, according to the affidavit.
Phillips' husband, 56-year-old Patrick Dean Phillips, said his wife had told him she turned their grandson over to a social worker. He said Gerren was completely mute and did not have control over his limbs.
According to the affidavit, Darlene Phillips was charged with murder for "intentionally leaving the child in a place where the child was unlikely to be located and, due to his age, physical disabilities, removal of feeding tube and medical supplies needed to maintain the child's health and his inability to make noise, he was unable to care for himself and died."
Susan Etheridge, an advocate for child abuse victims form more than 30 years in Dallas and Collin counties, said she is thrilled to see prosecutors seek a murder conviction in the case.
"When you leave him in a secluded place where he cant be seen, I'm sorry, I don't think she expected for him to be found," she said.
The boy's father, 41-year-old Jerry Joseph Isgrigg, is a Marine stationed in California. The child's mother, Nyki Phillips, was located in McAlester, Okla., and told authorities that she had left her son in the care of her mother.
NBC DFW's Shane Allen & Ellen Goldberg contributed to this report.