Proving that crime can pay, a convicted killer is set to inherit a quarter-million dollars from his victim.

Heroin addict Brandon Palladino, 24, will be living in the lap of luxury when he’s sprung from jail, where he’s serving time for killing his mother-in-law — an outcome that has the victim’s family fuming.

“It’s not justice. I don’t understand how he can profit from a crime,” said a tearful Donna Larsen, the sister of the woman Palladino killed in 2008, Dianne Edwards. “He’s going to come out of jail in his 40s with hundreds of thousands of dollars.”

Palladino has admitted he killed Edwards, 59, after she caught him trying to steal jewelry from her Long Island home.

He later made a deal to do 25 years in jail, minus time served, more than a year — avoiding the maximum of 25 years to life.

Edwards’ will bequeathed all of her worldly goods — about $431,000 — to her only daughter, Deanna Palladino, 23, who was never charged in the crime.

After Brandon was arrested in November 2009, for the murder, his wife used some of her mom’s $190,000 in savings to bankroll her husband’s defense, according to a Suffolk prosecutor.

Then Deanna died last February, leaving everything to her jailed husband.

“It’s an outrage. He can’t have that money — it’s just not right. It’s ludicrous,” said Larsen, who’d rather see the money go to the state or to charity.

She claims her dead niece, Deanna Palladino, was part of the robbery that led to the murder and took part in an attempted cover-up.

“She gave him the key to my sister’s house, and then they later went there together before the police were called. She was part of the cover-up and even pawned some of my sister’s jewelry. It’s a slap in the face,” said Larsen.

Larsen said she believes her niece may have committed suicide with a drug overdose because she could not face what she had done to her mother.

“How could she live with herself?” Larsen asked.

Larsen said she will ask Suffolk Supreme Court Justice Robert Doyle to scrap the plea-bargain deal he made with Palladino, unless the killer agrees to give up his victim’s remaining legacy — $241,000 from the sale of the Melville home where the murder took place.

Larsen said the killer and his wife went on a vacation cruise using the slain woman’s money before cops arrested him.

Palladino’s mom, Donna DiRusso, of Huntington Station, yesterday refused to comment.

“He took her life — he can’t take her money, too,” said Larsen’s husband, Andy.

“It’s ridiculous. How can a murderer walk away with his victim’s assets?”

kieran.crowley@nypost.com

