(CNN)Sheriff's deputies found a grisly and heartbreaking scene when they answered a 911 call at a Memphis apartment complex, authorities said Saturday.
Memphis mother accused of fatally stabbing 4 children
Four children, ages 4 years to 6 months, had been stabbed to death, Shelby County Sheriff Bill Oldham said.
The children's mother, Shaynthia Gardner, 29, was arrested at the scene and is accused of killing her children, Oldham said. Investigators are trying to determine a motive..
"One of the most difficult questions in any investigation always is, why did it occur?" Oldham said, according to CNN affiliate WMC.
A fifth child, a 7-year-old boy, escaped the mayhem, Oldham said.
"He is safe and in a place of protection until next of kin can be notified," he said.
The father of the four slain children was questioned, though he was not at home when the killings happened, authorities said, according to CNN affiliate WMC. The surviving boy has a different father, Oldham said.
The killings happened Friday afternoon at the Greens at Irene apartments in southeast Shelby County. The victims were a boy, 4, and three girls, ages 3, 2 and 6 months.
Gardner was charged with four counts of first-degree murder in perpetration of a felony aggravated child neglect, four counts of first-degree murder in perpetration of a felony aggravated child abuse, four counts of aggravated child neglect or endangerment and four counts of aggravated child abuse. Other charges may be filed, Oldham said.
Oldham said the sheriff's department is reeling from the killings. One of the department employees is an aunt to the slain children.
"It is certainly something that has impacted us as an organization and a family," he said.
Neighbors of the family said they are shocked and perplexed.
"I can't imagine what those babies do to make you do that," Trisha Johnson told WMC. "If you're having trouble, go and say you're having trouble. Everybody gets stressed out. Kids are home from school, you don't know what to do with them, you have no money to do with them, but you don't take their lives."