Maniac who randomly beat beloved security guard to death at NYC subway station found mentally unfit for trial

The madman charged with randomly pummeling a beloved security guard to death at a Brooklyn subway station has been found mentally unfit to stand trial, a court heard Friday.

David Mazariegos, 25, will be committed to a state psychiatric hospital after flunking a mental health exam — following the alleged merciless, unprovoked Oct. 7, 2025 killing of Nicola Tanzi, a 64-year-old security guard at MetroTech.

Brooklyn Supreme Court Judge Dineen Riviezzo revealed that Mazariegos — a struggling artist with an escalating rap sheet before the attack — had been “found unfit” for trial before wishing the maniac good luck.

“We will see you at some point at which you are better. Good luck with your treatment,” the judge said during a brief hearing, just before Mazareigos was handed over to the custody of mental health professionals.

Mazareigos, who appeared subdued and sleepy while wearing an orange prison outfit, will face first-degree murder and other charges if or when he’s deemed mentally fit to stand trial at a later date.

Prosecutors said Mazareigos punched Tanzi in the face at a security gate in the Jay Street-MetroTech station, near where the God-fearing Italian immigrant had worked for 15 years.

Mazareigos then allegedly repeatedly stomped on Tanzi until his body went “totally limp” — leaving him with a skull fracture, a crushed nasal bone and multiple other injuries to his face, prosecutors have said.

Tanzi, a devout Catholic, died a few hours later.

The brute stole the victim’s debit and credit cards to buy a samurai sword, which was found on him when police arrested him later in Times Squares, authorities have said.

Mazareigos, who infamously shined a broken-tooth smile after his arraignment, confessed to beating the victim, robbing him and “taking his spirt,” according to prosecutors.

His attorney, Zwi Wasserstein, declined to comment after Friday’s hearing.