A Clayton County man is accused of causing severe injuries to his girlfriend's 4-year-old, but hasn't been charged in connection with another child's death, according to police.

Kemra Nesta Matthew, 29, of a Jonesboro address, was arrested Wednesday and charged with first degree child cruelty and aggravated assault, Officer Eddie Soto with Clayton County police said. Matthew had a court appearance Friday morning before returning to jail, where he was being held without bond, according to booking records.

But Matthew's girlfriend denied he harmed her children, Channel 2 Action News reported.

"He's a hardworking, good man, so I'm not about to sit here and let nobody, I don't care who they are, do this to him. Period," Ashley Harvey said.

In an interview with investigators, Matthew denied any knowledge of how the child was injured, Soto said. Officers said Harvey's 4-year-old son, Ashton, told them Matthew punched him in the stomach, causing him to vomit, and punched his 2-year-old brother, Jayden.

Matthew was caring for his live-in girlfriend's four children on July 11 at the time the alleged abuse occurred, Soto said. All four siblings were transported to the hospital for treatment, but a 2-year-old did not survive, police previously said.

The cause of the child's death remains under investigation by the GBI, Soto said.

Police and firefighters were called to the Marquis Grande Apartments near Jonesboro on July 11 to investigate a report of four sick children, ranging in age from 8 months to 5 years, police previously said.

Matthew's criminal history includes spending nearly three years at Calhoun State Prison following a conviction on various drug charges, according to the Georgia Department of Corrections. He was incarcerated in June 2006 and released from prison in March 2009, records show.