CHICAGO (CBS) — The Illinois Department of Children and Family Services has launched an investigation, after a 1-year-old boy was shot and wounded in Uptown this week.

Police spent the day Tuesday searching for evidence in and around an apartment building where the boy’s family lived.

Police believe the child’s parents were fighting with a gun in their home Monday night, when the gun went off striking the boy.

The boy’s father first told police the boy was wounded by a stray bullet on the street a block away, but police said that was not true.

Police said the boy’s father walked into Weiss Memorial Hospital with the baby boy shortly after 7:30 p.m. He claimed someone had opened fire at him near Clarendon and Leland avenues, and shot the boy instead.

However, investigators soon had trouble corroborating the father’s story.

Investigators found blood in an elevator of the father’s apartment building near Clarendon and Eastwood Avenues, a block away from where the father claimed the shooting happened on the street. Guglielmi said police also found at least one shell casing and blood in the kitchen and living room of the family’s apartment.

Guglielmi said police have seized surveillance video from the apartment building and are reviewing the footage as they question the boy’s mother and father. Investigators also are combing the area around Weiss Hospital, searching for the gun from the shooting.

No charges had been filed as of Tuesday morning, but Guglielmi said charges are likely.

The boy was transferred to Lurie Children’s Hospital after his father brought him to Weiss, and the baby was in serious but stable condition.

The bullet ricocheted and hit the boy in the head, and did not penetrate his skull.