A Zachary man who claims he was under the influence of synthetic marijuana when he fatally beat, stabbed and shot his 11-month-old son in October 2017 pleaded guilty to manslaughter Monday.

Fabian Smith, 37, will face a prison term in the range of 15 to 40 years when he is sentenced Jan. 19 by state District Judge Eboni Johnson-Rose.

Smith had been scheduled to stand trial Monday on charges of second-degree murder and second-degree cruelty to a juvenile in the death of Jericho Smith on Oct. 14, 2017.

East Baton Rouge Parish prosecutors dismissed the cruelty charge Monday. A second-degree murder conviction would have put Smith behind bars for the rest of his life.

Smith's attorney, Rob Ray, and District Attorney Hillar Moore III decided to withhold comment until Smith is sentenced. Ray has said previously that Smith was intoxicated on synthetic marijuana at the time of his son's slaying.

Jericho died of multiple gunshot and stab wounds and blunt force injuries, coroner's officials have said. A gun and knife were found inside the home. The toddler was shot in the head and neck, and had gunshot residue around his face — an indication that he was shot at close range, Zachary police detective Enoch Sims testified at a hearing in late 2017.

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Smith was the only adult in his Hancock Street home at the time of Jericho’s death, police said. The baby’s mother was at work.

Zachary police detectives believe Smith could have been under the influence of “some type of substance” because he said he could not remember what happened “and the last thing that he could recall was picking up food from Burger King for the children,” a search warrant stated.

One of those detectives, Sims, testified previously that Smith told a neighbor, “I messed up, I messed up, I messed up.” Sims said Jericho’s then-2-year-old sibling told him, “My daddy killed the baby!”

Smith had been found competent to stand trial. Ray has said mental health experts opined that Smith's mental state at the time of the horrific crime was diminished due to his self-intoxication. Voluntary intoxication is not a legal defense to a crime.

Email Joe Gyan Jr. at jgyan@theadvocate.com.