Accused killer dad Luciano Frattolin stopped answering texts from his ex-wife when she asked him one heartbreaking question — when their daughter would be home, sources told The Post on Tuesday.

After some messages and calls going back and forth between the parents, Frattolin went radio-silent on the mom’s text requesting an update — and within a day, 9-year-old Melina Frattolin would be found dead, drowned by her dad and hidden under a log in a remote pond in upstate New York, law-enforcement sources said.

“Everyone is in shock,” a relative of the mom told the Canadian outlet La Presse. “The situation is causing immense stress within our family.”

Melina had been on a scheduled visitation with her father — a trip that included New York City — before her slaying Saturday night, sources said.

The young girl talked to her mom by phone just an hour before she was murdered — and nothing seemed amiss at the time, police said.

The child was due back home in Montreal later that night.

Frattolin and his ex, who split in 2019, had been having custody issues, sources said.

New York State Police are still building a picture of Frattolin’s movements over the weekend with his daughter.

Melina was reported missing around 10 p.m. on Saturday by her father, who claimed that she had been taken by two men in a white van while he stepped out of his silver 2024 Toyota Prius to urinate close to Exit 22 of I-87 near Lake George.

An Amber Alert was issued early Sunday but that afternoon, Melina’s body was discovered in a shallow waterway under a log near the town of Ticonderoga some 30 miles from where the reported abduction took place.

A preliminary autopsy showed that her cause of death was asphyxia by drowning, authorities said Tuesday.

Frattolin and Melina, both from Montreal, entered the US legally for a vacation July 11, according to police.

They were expected to return Saturday, at which time Melina would be returned to the custody of her mother in Montreal.

Father and daughter were both seen on video surveillance at a restaurant in Saratoga Springs at about 5:30 p.m. Saturday.

Every morning, the NY POSTcast offers a deep dive into the headlines with the Post’s signature mix of politics, business, pop culture, true crime and everything in between. Subscribe here!

Melina spoke to her mother over the phone at around 6:30 p.m., according to investigators.

Sources said she was dead within two hours.

Frattolin, who has no criminal record, is currently involved in five separate lawsuits, all filed this year, four of which he is the plaintiff, according to court records seen by the Montreal Gazette.

In one case, he is being sued for more than $83,000 by a bank in the lawsuit in which he is the defendant.

Frattolin had owned a small Montreal bed-and-breakfast called Gîte Bernard in the Mile End neighborhood but sold the property around six months ago, according to Jeremy Gravelle, who owns a cafe on the same street.

The suspect split his time between Canada and his father’s home country of Italy, Gravelle told La Presse, adding that he had seen Frattolin just two or three times in the past 18 months.

“He was very reserved,” Gravelle added, while other workers on the street described the hotel as largely empty.

“It’s really a ghost business. You see people coming and going with their suitcases. It looks more like an AirBnB than a bed and breakfast,” said Guy Lavoie, who works at a nearby vinyl record store, to La Presse.

“I’ve never even seen the owner once.”

Frattolin also had been engaged in a legal dispute with a business partner with whom he owned the bed and breakfast, according to recent court documents seen by La Presse.

He had used the revenue from the property to pay his daughter’s child support and also stored his daughter’s clothes and toys in the building, according to court documents.

But this past spring, the building’s owner barred him from entering the building, Frattolin claimed in a lawsuit filed in April.

He also accused his business partner of using the company’s credit card to renovate the building and illegally operate the bed and breakfast under a different name, the lawsuit alleges.

Frattolin even accused his business partner of threatening to prevent him from entering Quebec “because of unpaid taxes from his company,” the suit states.

The business partner allegedly told the building owners that the now-suspected killer was trying to flee the country, something Frattolin said was untrue.