Updated

A man has been convicted of murder for stabbing a good Samaritan who came to the aid of a woman and her infant he was chasing with a knife.

The Delaware attorney general's office said in a news release Friday that a jury found 26-year-old Calvin Hooker III guilty but mentally ill on a second-degree murder charge.

Prosecutors say Hooker repeatedly stabbed 27-year-old Thomas Cottingham in September 2015. Authorities say Cottingham intervened when Hooker, holding a knife over his head, chased a woman pushing her infant in a stroller in Wilmington.

The woman testified against Hooker at his trial.

Hooker faces a maximum sentence of life in prison. He will be confined and treated at a Delaware psychiatric hospital.