WHITE PLAINS — A Brooklyn man and his sister were found guilty yesterday of orchestrating the killings of the woman’s millionaire husband and his mother in a grab for the family estate.

A federal jury convicted Narcy Novack of Fort Lauderdale on counts alleging she caused the savage 2009 beatings of Ben Novack Jr. in a suburban New York hotel room and Bernice Novack at her Fort Lauderdale home.

Novack and her brother, Cristobal Veliz, of Brooklyn, both were also convicted of charges including racketeering, domestic violence, stalking, money laundering and witness tampering.

They could get life in prison when sentenced on Nov. 1.

Novack chose not to attend the reading of the verdict. Veliz was present and showed no emotion.

Novack’s lawyer, Howard Tanner, said afterward, “We put on our defense, and the jury has spoken. They were a conscientious jury.”

Prosecutors said Novack and Veliz were motivated by “jealousy, retribution and greed” when they hired the thugs who carried out the killings. They said Novack feared that her husband, who was having an affair, would divorce her, and that a prenuptial agreement would bar her from the multimillion-dollar family estate.

Ben Novack Jr. had a successful travel company. His father built the storied Fontainebleau hotel in Miami Beach, a celebrity hangout in the 1950s and ’60s that appeared in the movies “Scarface” and “Goldfinger.”

The defense had tried to blame the killings on Narcy Novack’s daughter, whose sons will now inherit the estate.

Prosecutors said Novack, 55, paid Veliz, 58, to hire Miami thugs to assault the victims. The killers testified that Veliz recruited them and relayed instructions from Novack on how to carry out the killings.

They testified that those instructions included blinding Ben Novack Jr. — his eyes were slashed with a utility knife — and bashing 86-year-old Bernice Novack in the teeth with a plumber’s wrench.

The killers also testified that Narcy Novack identified her husband to them in advance by stroking his hair in a restaurant as they watched.

They said that on the day of Ben Novack’s killing, Narcy Novack called Veliz, who said: “Well, she’s ready. Let’s go.” One said that when they got to the Hilton hotel in Rye Brook, N.Y., where Ben Novack’s company was running an Amway convention, Narcy Novack motioned them into her room, directed them to her sleeping husband, gave them a pillow to muffle his screams and questioned them afterward to make sure he had been blinded.

“She shows them where her husband is, she ushers them into the room and they inflict a vicious, brutal attack on Ben Novack,” said prosecutor Andrew Dember.

One key witness was Rebecca Bliss, a former prostitute and porn actress, who said she was having an affair with Ben Novack when he was killed.

She said Narcy Novack tried to buy her off for $10,000 and told her, “If she couldn’t have him, no other woman was going to have him.”

Another witness, Alejandro Gutierrez-Garcia, said he killed Bernice Novack by slamming her in the head with a wrench in the driveway of her home on April 4, 2009. He and Joel Gonzalez testified that they beat Ben Novack to death with dumbbells three months later.

Grisly crime scene photos were shown to the jury.

Another Brooklyn man, Denis Ramirez, pled guilty to being the driver for Ben Novack’s murder. And his cousin then drove the killers from Brooklyn to Miami.

Bernice Novack’s death was originally ruled an accident, despite her broken jaw and blood smeared on the walls of her house. It was reclassified a homicide after Narcy Novack’s arrest in the death of her husband.

Garcia said the plan was to beat up the victims, not kill them. He said Ben Novack was to be injured so severely he would have to retire and Narcy Novack and Veliz would take over his travel company. At first the plan included cutting off Novack’s testicles, but that evolved into slashing his eyes, he said.

He said Veliz promised him $15,000 and “a good tip.”

Both defendants are natives of Ecuador.

The family intrigue in the case deepened when the defense strategy turned out to be blaming May Abad, who was Narcy Novack’s daughter and Ben Novack’s stepdaughter.

Defense attorneys said Abad, who wasn’t charged, could benefit by ordering the killings and framing her mother because her two sons would inherit the bulk of the family estate — which includes Ben Novack’s large collection of Batman memorabilia — if Narcy Novack were convicted.

“She’s the one who has a lot to gain,” said Veliz’s lawyer, Lawrence Sheehan. Veliz testified that he had seen Abad with the killers and claimed she had kidnapped him.

Abad didn’t testify, and her lawyer didn’t return calls seeking comment. Abad told the Miami Herald in April that trying to blame her stepfather’s murder on her was “a joke.”

“They are going to say whatever they can,” she said.

Narcy Novack didn’t testify at the trial, though she spoke to investigators for hours after the killing and said, “Only a monster can do this kind of evil thing.”

Veliz held the stand for days, repeatedly denying the prosecution’s account but sometimes stumbling to explain away credit card records, cellphone logs and an ATM surveillance video. He denied that he went to a Kmart near Miami and bought the dumbbells, one pink and one blue, that were used to bash Ben Novack.