A Tennessee man has been charged with the murder of a 4-month-old baby — who he allegedly killed after learning that he wasn’t the infant’s biological father.

CTV News reports that Jose Avila-Agurcia, 33, is being held on suspicion of murder after he allegedly beat 4-month-old Alexander Lizondro-Chacon to death.

According to an affidavit obtained by the Commercial Appeal, officers responded to a call about an unresponsive infant at a Memphis residence on April 12. The baby’s mother Mercy Lizondro-Chacon reportedly said he was struggling to breathe, and the infant died after being transported to a nearby hospital.

Initially, both Lizondro-Chacon and Avila-Agurcia told investigators that they did not know how the baby was injured and that they had both been caring for him. But more than a week after Alexander’s death, Lizondro-Chacon reportedly told investigators that Lizondro-Chacon had admitted to hitting the baby once he learned that he was not Alexander’s biological father.

In addition to the head trauma, the infant reportedly had a fractured skull and rib as well as pneumonia.

The suspect is being held without bond at the Shelby County Jail, and is due in court on Thursday.