A nearly seven-minute 911 call was submitted as evidence Wednesday in the case against a former NYPD officer and his ex-fiancée in the death of the officer's 8-year-old son Thomas Valva.

On the call, Michael Valva, Thomas' father, is heard telling the operator that he's performing CPR on his son who he said fell and hit his head in the driveway at their Center Moriches home.

Valva says on the tape, "I don't know if he's breathing or not. I don't know if his heart stopped. He fell down on his way to the bus. He banged his head pretty good. I brought him in, and I'm doing CPR right now."

LISTEN: Michael Valva's 911 call for his 8-year-old son Thomas

Valva and his former fiancée Angela Pollina are both charged with murder in connection with the death of Thomas in January 2020.

Prosecutors say the child died of hypothermia after the pair forced him to sleep in a freezing garage as a punishment. Both Valva and Pollina wiped away tears as the 911 tape played during a pre-trial hearing in Riverhead.

John Loturco, Valva's attorney, responded in court to questions about why Valva is heard laughing at one point on the call. "In my opinion that is a reaction, a nervous reaction," says Loturco.

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This is the second day of listening to evidence to determine what will be allowed at trial. At issue is whether the Suffolk detectives who gathered the evidence illegally searched--staying after the emergency situation had been resolved.

That evidence includes videotape from several cameras including inside Valva's home. A detective testified that Pollina gave police the password to get the video.

"It's 99% likely she will testify at the hearing, which is unusual, but she's got nothing to hide," says Matt Touhy, Pollina's attorney.

Loturco says the pair is blaming each other so in his opinion the trials should be separated.

"Clearly Angela and Michael were not the parents of the year in any way," says Loturco. "They should not have been parents of these autistic children, but they are not murderers."

The pre-trial hearings are expected to last for the rest of the week.

Both Valva and Pollina have pleaded not guilty to second-degree murder and child endangerment charges.