The devastated mother of the innocent 8-year-old whose veteran NYPD cop father allegedly kept the child in an unheated garage overnight, causing him to freeze to death claimed that her children were abused at the hands of their dad for years and was ignored by those with the authority to help.

“There are so many people responsible for this tragedy,” Justyna Zubko-Valva, 36, told The Post Friday just hours after her ex-husband, Michael Valva, 40, and his fiancée, Angela Pollina, 42, were charged with murder in the death of little Thomas Valva.

Thomas, who has autism according to his mom, died of hypothermia on Jan. 17, officials said.

“The institutions that are supposed to protect the children protect the abusers,” said Zubko-Valva who claimed that she reported to law enforcement and child protective agencies and judges about the alleged abuse of her three young boys.

Zubko-Valva, who says she lost custody of her three children in 2017, said she “went everywhere” to report that her children were in danger.

The mom alleged “severe” abuse of the children that included “physical, emotional, and also sexual abuse.”

A range of officials “knew exactly that the children needed help. That they were being abused, and you know, brainwashed. That food was being withheld from them as a form of punishment.”

“They did absolutely nothing,” said Zubko-Valva, who also has a 10-year-old and a 6-year-old that were living with Valva and Pollina.

“Trust me, I wrote to everybody. I asked for help. I beg the judge to remove the children. Immediately I begged the CPS caseworker 10 days before my son’s death,” she said, adding, the caseworker then closed the report.

Zubko-Valva said during court proceedings over the years she told judges: “My children are gonna die from the sadistic and abusive care of Michael Valva and Angela Pollina. I told them everything.”

The helpless mother even detailed the alleged abuse on a Twitter account she created in January 2018 under the name “StandAgainstChildAbuse.”

A 2018 report from the East Moriches School District posted in a tweet details how Thomas and his older brother, Anthony, were being neglected by Valva and Pollina.

“Biggest concern is that Mr. Valva and his fiancée Angela do not understand the depth of Anthony and Thomas’s disabilities,” read the letter written by a school psychologist.

The letter went on to say that “both Anthony and Thomas come into school hungry and frequently say they did not eat breakfast because they did not ask for breakfast or got in trouble.”

“The boys were afraid to go to the nurse’s office for a while and they said it was because they were directed by Mr. Valva and Angela not to go to the nurse’s office. This occurred shortly after the school nurse became involved in a CPS case because Thomas has multiple bruises on his bottom from Dad,” the letter read.

Another school letter posted to the account states: “Anthony and Thomas have stated that they were not allowed to eat breakfast because they did not use their manners, say good morning to Angela or were doing nothing. They have come in crying because of this.”

“The boys come in hungry and most days state that they have not eaten breakfast,” says the letter, which noted that “both boys were coming in with visible dirt on their bodies for days in a row,” and that Anthony lost 11 pounds in nine months, while Thomas gained one pound in 20 months — despite both being growing boys.

The school district would not verify the letters, but Charles Russo, the Superintendent of Schools, expressed the school’s condolences in a statement.

“Thomas was a tender, loving boy who made tremendous gains during the short time he was a student in East Moriches,” Russo said, adding, “While the district legally cannot comment on any specific case, it aggressively reports to the proper authorities child abuse when it is suspected.”

Meanwhile, Suffolk Police Commissioner Geraldine Hart said Friday that Thomas “was subjected to freezing temperatures” in the “unheated garage” of Valva and Pollina’s Long Island home in Center Moriches “overnight” Jan. 16 into Jan. 17 when the temperatures outside were just 19 degrees.

A Suffolk County source said that the day before Valva got angry with Thomas and beat the boy.

As punishment, Thomas was ordered to stay in the garage, according to the source.

Thomas’ lifeless body was found in the garage the next day and the source says Valva put the boy’s body in a warm bath in order to raise his body temperature.

Valva reported to police that his son fell in the driveway.

Medics rushed the boy to Long Island Community Hospital and when he arrived there his body temperature was just 76 degrees, according to Hart.

Additional reporting by Anabel Sosa