The incident happened early Wednesday at a home on Thistle Trace, which is north of Guess Road off St. Mary's Road in Durham/Hillsborough's Hardscrabble Plantation subdivision.
Deputies say they received a call from inside the home around 12:30 a.m. When they arrived at the scene, they discovered 4-year-old Blake Mitchell not breathing and his father injured.
Investigators believe the boy was smothered.
His father -- 46-year-old Joseph Mitchell -- now faces one count of murder and two counts of attempted murder.
Although authorities are not able to release many details because the investigation is ongoing, Lieutenant Stan Harris says the 4-year-old's siblings -- a 10-year-old and a 13-year-old -- along with the children's mother were in the house at the time of the incident.
After smothering the child, detectives say Mitchell apparently tried to suffocate his two other children, then stabbed himself.
Authorities say Mitchell was taken to the hospital and when he is released, he will be taken to the Durham County Magistrate where he will be formally charged.
According to the 911 call released Wednesday afternoon, the 4-year-old's maternal grandfather, who also lives in the house, made the call to authorities.
The man told the operator that his daughter discovered the toddler unresponsive in his room, and the child's father was locked in an office on the second floor. The grandfather said he didn't know what happened but believed the child's father may have hurt the boy.
The grandfather went on to say he had just returned home for the evening when he was alerted to the situation.
The child's mother and a sibling can be heard on the 911 call performing CPR until EMS workers arrived. Workers transported the boy to the hospital but were unable to revive him.
According to the maternal grandfather, Mitchell was a former EMS worker but had been out of work for about a year. He described his son-in-law as an easygoing, nice guy.
Mitchell's father, Eugene Mitchell, said he found out what happened when another one of his sons came to his home and delivered a frantic message.
"'Joseph's son is dead!'" Eugene Mitchell recalled his son yelling. "Come on Daddy, come on!"
Eugene Mitchell said hearing the news made him flip out. "You're hearing about your grandchildren," he said.
"He loved his children, the wife got along well together, the father-in-law," Eugene Mitchell said. "They were always, they were always happy, a happy family. Always. No problems at all. That's why it shocked me when this happened."
Lieutenant Harris says the entire family is struggling to cope with the situation.
"We just try to reassure them, the best we can," Lt. Harris said. "In a situation like this, you can only console them so much. We just ask everybody to be patient and let us do our job."
The Mitchell's neighbors, Cynthia and Tim Ross, say they've known the Mitchell family for about 10 years.
"They were just active in the community and this is so out of character," Cynthia Ross said. "No one can understand."
"Our kids play with their kids," Tim Ross said. "It's been real difficult, but we're just astonished. We just don't know what to make of it all."
They say Mitchell had once worked in the Durham County medical services but had been out of work for about a year.
Meanwhile, court documents show the family's money troubles started in 2005. The family's home was in the process of foreclosing, but investigators haven't said whether that was the motive.