Greg Shillinglaw and Lee Higgins

As his then-fiancee's severely disabled daughter was "tense and moaning," wasting away at their Yonkers apartment, Oscar Thomas met with a probation officer, shopped at a video game store and even dined at IHOP.

By the time he returned home roughly three-and-a-half hours later, 8-year-old Alayah-Rose Savarese, who had cerebral palsy and could not speak, walk or eat, was dead in the squalid apartment, where Thomas left her with a friend who crashed for the night, prosecutors say. Recent court filings offer new details about the the little girl's case, including that she was found dead on June 25, 2012 in a dirty T-shirt and diaper weighing only 33 pounds.

Lawyers for her mother, Nicole Diggs, a New York City special education teacher, maintain that she took good care of Alayah and want the court to dismiss charges of criminally negligent homicide and endangering the welfare of a child. Thomas, who was "Mr. Mom" and watched the child during the day, is facing the same charges.

Prosecutors say there was a pattern of neglect, as Alayah was underfed for years, despite her mother having access to a $2.1 million trust established for her care. Diggs' lawyers contend it has nothing to do with money that stemmed from a settlement in a medical malpractice case against the hospital where Alayah was born.

"This case is about a young woman whose child was born disastrously compromised," lawyer Arlene R. Popkin wrote. "The prosecution now seeks to hold Ms. Diggs criminally liable for not having done enough, or done well enough to further forestall that death."

Her lawyer added there isn't the slightest shred of evidence Diggs got rid of her daughter to recoup the money. If there was, the 31-year-old Cornell University graduate would be facing a murder charge. (Even if she's convicted, Diggs stands to inherit about $1 million from the girl's trust fund, with Alayah's biological father getting the other half.)

Prosecutors say Diggs failed to take Alayah to any follow-up doctor's appointments after she had surgery to loosen her limbs in October 2011 and also didn't take her to two specialists despite agreeing to during a January 2012 meeting with school officials and social workers.

Diggs rejected opportunities for help, including a week before her daughter's death, when caseworkers were investigating a complaint Alayah had unexplained bruises and missed half the school year. Responding to a suggestion that she hire a health aide, Diggs said she didn't want the government to "recoup any money from the settlement," a caseworker's notes say.

She reportedly told the caseworker, "The bottom line is that I do not want anyone to come and help me with Alayah. I have been taking care of her for the past eight years, I can keep doing so." Asked where Thomas was, Diggs smiled and said, "You know he doesn't like CPS. He stepped out for awhile."

The couple was familiar with child welfare authorities. Prior to Alayah's death, six complaints had been made with the state regarding her care, including that she was filthy, underfed, frequently absent from school and missed physical therapy appointments.

A day after Alayah died, Thomas, 28, told a caseworker he loved the girl and "was treated like a criminal" by police, which made him "feel like a monster." Diggs wondered whether she'd still be able to move into a $500,000 house she bought in Ulster County with money from the trust. The house was going to be equipped for Alayah's needs.

"Ms. Diggs told this worker that she isn't sure now that Alayah has passed if she is allowed to move into the home in Ulster County...Regardless, Ms. Diggs said that she can't live in that same apartment on Ashburton. She added that the people there are already talking about how she neglected her daughter and didn't take care of her."

Popkin says it's unclear why Thomas is being charged. He was not Alayah's parent, only babysitting for her when Diggs went to work and the girl was not at school, Popkin said. She is moving to have them tried separately, because she says Thomas' criminal record — he was convicted of attempted assault — and marijuana use would make it tough for Diggs to get a fair trial.

Thomas' attorney, Michael Rubin, declined comment. Thomas remains held at the Westchester County jail while Diggs is out on $25,000 bail. After her arraignment in June, she was reassigned from her teaching duties at P.S. 152 Evergreen in the Bronx and barred from having access to students.

Twitter: @gshilly