Suffolk County is launching an internal investigation into how its Department of Social Services handled the case of an 8-year-old Long Island boy with autism whose NYPD cop dad allegedly left him in the family’s garage overnight, causing him to freeze to death.

The probe, which will be overseen by DSS Commissioner Frances Pierre, will look into “departmental procedures and actions in this specific case,” Suffolk County Executive Steve Bellone announced Monday night.

Little Thomas Valva was found unresponsive at his Center Moriches home Jan. 17 and rushed to an area hospital, where he was pronounced dead of hypothermia.

Michael Valva, 40, a 15-year police veteran, and his fiancée, Angela Pollina, 42, were charged with second-degree murder Friday after police say the pair subjected the boy to “freezing temperatures” in their “unheated garage” for an entire night — when temps outside were a bone-chilling 19 degrees.

“As a parent, I am horrified by what happened to this beautiful boy,” Bellone said. “As county executive, I want to know if there’s anything else that could have been done under existing law to prevent this from happening.

“Beyond that, I want to know if anything in this case suggests that changes should be made to existing policy or law.”

The boy’s biological mom, Justyna Zubko-Valva, says she “unlawfully” lost custody of Thomas and her two other sons, ages 6 and 10, in 2017 amid a divorce battle with Valva and that authorities ignored her repeated claims that the kids were being abused by their dad.

According to Bellone, the internal review of the case “will also recommend any changes to existing policies, procedures, regulations or laws that should be implemented to help prevent future tragedies.”

Suffolk County will work with the state Office of Children and Family Services and the Suffolk County DA’s Office as it conducts an independent review of the case, Bellone said.

Additionally, a task force will be established “to review all Child Protective Services policies and procedures as they relate to children with autism and other developmental disabilities,” according to Bellone.

“The task force will be charged with reviewing procedures for how services are provided to children with autism or other developmental challenges under current law, determine if the current system leaves children with disabilities more vulnerable, and whether additional safeguards need to be enacted,” Bellone said.

The Post previously revealed that the state Office of Children and Family Services recorded a complaint about a child being forced to sleep in the garage at Valva’s home in 2019 — but Suffolk County Child Protective Services determined it to be “unfounded.”

The record, from a phone call logged Feb. 27, 2019, stated that Valva’s son Anthony was forced to sleep in the garage — the same one where Thomas was stashed — because he was urinating in his bed.

On Monday, Zubko-Valva, a corrections officer on Rikers Island, was awarded temporary custody of her two surviving sons.