CNN  — 

A New York transit police officer and his fiancée were arrested Friday and charged with murder in connection with the death of the officer’s 8-year-old son, Suffolk County police said Friday.

Michael Valva, 40, and Angela Pollina, 42, were both charged with second-degree murder. The couple allegedly left Valva’s son, Thomas, overnight in the unheated, unfinished garage of their Long Island home last week, Suffolk County Police Commissioner Geraldine Hart said in a press conference.

After finding him unresponsive, Valva called local police, saying Thomas had fallen in the driveway while waiting for the bus, Hart said. When police arrived, Valva was performing CPR on Thomas in the home’s basement, Hard said. Thomas was transported to Long Island Community Hospital, where he was pronounced dead.

Hart said the temperature that night had been 19 degrees and Thomas’s body temperature was 76 degrees. The medical examiner had ruled his death a homicide with hypothermia as a contributing factor, she said.

“We have determined that Thomas was never in the driveway that morning, and he suffered head and facial injuries that were not consistent with his father’s account,” Hart said.

Valva has been a police officer in New York City since 2005, the department confirmed. He has been suspended without pay, according to police spokeswoman Detective Sophia Mason.

Both Valva and Pollina have pled not guilty, said Sheila Kelly, a spokeswoman for the Suffolk County District Attorney’s office. Both are still in custody after prosecutor applied for them to be held without bail, Kelly said.

Pollina’s attorney, Matthew Tuohy, told CNN that while Thomas’s death was a “tragedy,” she did not play a role in his death.

“I think that the case against her is extremely weak,” Tuohy said. “It is purely speculation and conjecture at this point.”

Valva’s attorney, Austin Manghan, declined to comment.

Besides Thomas, the couple had custody of Valva’s other sons, ages 6 and 10, and Pollina’s 6-year-old and 11-year-old twin daughters. Hart said police reviewed audio and video recordings captured by the home’s indoor/outdoor home surveillance system and determined that the couple were closely monitoring the activities and conversations of the six children.

Police believe that Thomas and his older brother were deprived of food and kept in freezing temperatures as punishment, Hart said.

“We are still investigating the extent of the abuse, and if it extended to all the children,” Hart said.

The children were removed from the home on January 17.

The Suffolk County Department of Social Services said it had investigated multiple complaints against the household, including a petition for child neglect in 2018. A judge ordered court-ordered home supervision and mandated that Valva and Pollina enroll in a positive parenting program.