Police arrested Antonio Cardenas-Rico and charged him with two counts of murder, Gwinnett County police Cpl. Jake Smith said.
Three-year-old Bradley Garcia and 1-year-old Edward Garcia were found stabbed to death in the home near Lawrenceville. Their father, 23-year-old Elvis Garcia, and another 3-year-old brother were hospitalized with stab wounds. The 3-year-olds are twins, Smith said.
Smith said at a news conference that the mainly suburban county on Atlanta's outskirts has seen grisly killings before, but "this one shocks the conscience a little bit due to the innocence and youth of the victims."
Police who responded to a 911 call around 6:30 p.m. Wednesday found Elvis Garcia outside with multiple stab wounds. He's the one who called police. The children were found in the finished basement of the house.
The family knew Cardenas-Rico but police declined to disclose the nature of their relationship.
Police say the children's mother and an older sister weren't home at the time and were found unhurt.
Cardenas-Rico had his first court appearance before a magistrate judge Thursday and was being held without bond. His next court date is Feb. 16. Matt Crosby, a lawyer appointed to represent Cardenas-Rico, did not immediately return a call seeking comment.