DENVER -- Three felony charges have been filed against the couple allegedly involved in the death of 7-year- old Chandler Grafner.

The Denver District Attorney's Office said 26-year-old Jon Phillips and 21-year-old Sarah Berry intentionally and deliberately malnourished and mistreated the boy, who is not biologically related to them.

The couple are both charged with first-degree murder causing the death of a child under 12, child abuse resulting in death, and first-degree murder after deliberation.

The 7-year-old boy weighed less than 30 pounds and was found by police suffering from cardiac arrest. He was reportedly kept in the couple's closet.

Sources at the boy's former elementary school confirm to 7NEWS that there were concerns about his well-being for some time and that those concerns were well documented. A teacher at Grafner's school repeatedly reported signs of neglect, the Denver Post reported. Investigators visited the couple's apartment but found nothing unusual.

Grafner's maternal grandmother talked exclusively to 7NEWS, saying that Chandler and his half-brother, Dominick Phillips, were taken away from her home.

Both Dominick and Chandler share the same mother but they were removed from her care because of her drug problem, their maternal grandmother, Sandra Younger said.

Younger said that she fought for custody of the boys but lost. Dominick's biological father, Jon Phillips, was given legal custody of both boys.

"I didn't want him (Phillips) to have them. I just didn't have a good feeling about it. And I told the social worker, but she said there's nothing she could do about a 'bad feeling,'" said Younger.

"(Social Services) also said that because the boys were sleeping on a large couch in my living room, and didn't have twin beds in a room of their own, that I was not a good candidate," said Younger.

Younger said the boys were in good hands with her. She is angry and distraught, saying that her beautiful 7-year-old grandson shouldn't have died.

"They were loved, and they were safe. They were well taken care of here. They were well-fed. You can ask any of the neighbors. They were happy with virtually no needs and no wants," said Younger.

Dominick, who is 5, is now in foster care.

Phillips and Berry are being held without bond at the Denver County Jail. They are scheduled to appear in Denver County Court on Monday to be formally advised of the charges. If they are convicted, they face life in prison without the possibility of parole.

They were taken into custody on Sunday, when police were called to the their apartment on South Tamarac Drive and Hampden Avenue.