The suspect, 46-year-old Joe Mitchell, who is the children's father, has been discharged from Duke Hospital and transported to prison for safekeeping.
Mitchell faced a magistrate at the hospital were he was officially charged with murder and two counts of attempted murder Friday afternoon.
Instead of the Durham County Jail, Mitchell will stay at Raleigh's Central Prison, because of concern over his attempted suicide and public outrage over the case.
Investigators say Mitchell suffocated his 4-year-old son, Blake Mitchell, early Wednesday at their home on Thistle Trace, which is north of Guess Road off St. Mary's Road in Durham/Hillsborough's Hardscrabble Plantation subdivision. He then locked himself inside a room where he attempted to take his own life.
His wife and older children were also at home at the time. The boy's mother and neighbors desperately tried to revive the 4-year-old.
The new warrants show authorities seized a mask, a knife, two gloves and an envelope from BB&T addressed to Mitchell.
"It's just part of all of the totality of the evidence that we have, we're not reading anything into the mask," Harris said. "We are investigating. We will process the mask as we normally would."
Investigators say they're digging into motives from finances to mental illness.
Court records show the family was having financial problems and their home was in foreclosure. Also in the warrants, authorities say they had to use force to gain entry into the room where Mitchell was.
"Try to wrap your mind around this incident," Harris said. "Any father to inflict bodily harm on any child, we'll be looking into his mental status."
Meanwhile, the victim's older siblings are preparing to return to their Durham school, Voyager Academy.
Principal Carl Forsyth tells ABC11 Eyewitness News that the public can make donations to a memorial fund for Blake Mitchell to help pay for funeral expenses.
"The outpouring of support for the Mitchell family has been heartwarming," Forsyth said.
If you would like to make a donation, go to the Voyager Academy's website at www.voyageracademy.net