Four young children were stabbed to death in a gated apartment complex in suburban Memphis on Friday, and police took their mother into custody for questioning. She has not been charged, according to AP. Deputies were called to the complex in unincorporated Shelby County shortly before 1 p.m., said county Sheriff Bill Oldham, who did not specifically allege that the mother had stabbed the children. "This is an egregious act of evil that has shocked us to our core," Oldham said. "I will never understand how anyone can do this." Officials have not released the ages of the children, but sheriff's office spokesman Earle Farrell said deputies responding to the scene called them "babies." "What can you say?" said neighbor Sean Ahearn. "It's just a terrible, terrible thing." Ahearn said he didn't know the family by name, but that he often saw the children, who all appeared to be under age 6, playing in the front yard. They liked to pet his dog when he was taking it for a walk, he said. "From what I saw, they were very open and friendly kids," he said. "You never imagine that this kind of thing could happen." The investigation is in a very preliminary stage and investigators do not know if the mother had any mental health issues, Oldham said. He said authorities are working to notify the next of kin and won't release names before that. "One of the most difficult questions in any investigation is always, 'Why did this happen?'" he said. Oldham said the district attorney general's special victims' unit has been called in and Shelby County Mayor Mark Luttrell has promised all resources necessary for the investigation. County Commissioner Mark Billingsley also said the county would work to help the family of the children recover. "It's just a very sad day," he said. "It's really beyond words, quite frankly." The apartment where the stabbing occurred is in a gated community with a golf course called The Greens at Irene. On Friday afternoon, deputies were standing at the gate house questioning motorists as they drove into the neighborhood. Resident Patricia Johnson spoke with reporters from her car Friday afternoon. She said she wasn't allowed to leave for two hours as deputies investigated the scene. She has a child, and said she burst into tears when she heard about the killings. "I can't fathom that," she said. "What would babies do to make you do that?" The state Department of Children's Service has offered its assistance to local law enforcement, but has no record of interaction with the slain children, said spokesman Rob Johnson. "We've done an exhaustive search and we are not aware of any contact with this family," he said. The news triggered painful memories for Johnson and others in Memphis: In 2008, a man's bloody rampage in the city left six dead, including two children, ages 2 and 4. Jessie Dotson was convicted of shooting his brother during an argument at a house on Lester Street, then attacking everyone else in the house with a gun, boards and knives in an attempt to eliminate witnesses. Three other children were stabbed but survived, including a 2-month-old girl and 9-year-old boy, who was found in a bathtub with a 4 آ1⁄2-inch knife blade embedded in his skull. The survivors are known as the "miracles of Lester Street." Dotson was convicted and sentenced to death in 2010.