Calhoun County Sheriff Greg Pollan said Tyler Haire, 17, has been charged with aggravated assault after he called authorities to his County Road 433 home at 12:40 p.m.
"Paramedics and EMT's were already on the scene when our deputies arrived and found a woman in the kitchen with a 10-inch knife in her back," said Pollan. "The victim, Shelia Hughes, 45, was airlifted to Tupelo and is still there in critical condition."
Pollan said Haire is currently being held on $200,000 bond.
"The best we can tell he and his father's girlfriend got into an argument and she was stabbed once," said Pollan. "He (Haire) said he blacked out and when he came to she was on the floor with a knife in her back."
Pollan said Hughes and Haire were the only people at home at the time of the incident and the father arrived shortly before medical crews.
"Haire found an old cell phone and dialed 911," said Pollan. "He also told his father what was going on when he arrived. We would love to get a statement from the victim, but that is not possible at this time."
Pollan said the family had recently moved from Alabama to Calhoun County and investigators are checking with authorities in Alabama. Pollan said the investigation is continuing.
Pollan said the charges against Haire could be upgraded if the victim's condition changes for the worst.