A Goldman Sachs senior analyst disappeared early Saturday morning after attending a concert at The Brooklyn Mirage — the same Big Apple venue another man tried to get into before he was found dead several weeks ago, authorities and law enforcement sources said.

John Castic, 27, vanished after leaving the Williamsburg hotspot around 3 a.m. following a performance by electronic music group Zeds Dead, according to the NYPD and his “best friend” Sara Kostecka.

Kostecka shared news about Castic’s disappearance in a Monday Facebook post, where she revealed the pair are supposed to be together at her brother’s upcoming wedding.

“Any information would be greatly appreciated, as well as sharing this to anyone in NYC that might have seen him,” Kostecka said.

“I’ve heard rumors from people about being asked to hop in a taxi/ cab from some creepy people near the Mirage – reminder to stay safe and check in on your friends,” she additionally wrote. I’m supposed to walk with him in my brothers wedding next week.. we just wanna find John.”

Castic, who lives in Lower Manhattan, is described as 6-foot-3 and 180 pounds, police said. The Illinois native graduated from DePaul University and began his job at Goldman Sachs last August, according to his Facebook page.

He was last seen wearing a white and navy blue floral shirt with khaki pants, according to a missing persons flier.

Another friend told Fox News Digital that Castic’s phone died after he left the venue and hasn’t been turned on since.

“We’re absolutely very worried about him,” Jonah Shales reportedly said. “No one has had any contact with him.”

Castic is the second person to go missing in recent weeks after going to The Brooklyn Mirage, one of three concert spaces housed at the Avant Gardner that has a total capacity of 6,000 people.

The other man, Karl Clemente, 27, was turned away from the venue because “he allegedly drank alcohol” on June 11 when he went with a group of friends to see a concert, electronic music publication EDM Identity reported, citing a friend’s Facebook post. 

Clemente’s body was found days later about half-a-mile away in Newtown Creek behind a warehouse, according to sources.

Clemente’s death was not considered suspicious, sources said. 

In March, Gothamist reported about The Mirage’s battle with the State Liquor Authority.

SLA officials lodged numerous concerns about “rampant” drug use and noted a number of people who died that attended the events there, the outlet reported.

Since 2017, three people who attended different Avant Gardner events ended up dying of accidental drug overdoses, Gothamist reported.

A 41-year-old man died in 2017, a 21-year-old woman in 2018 and a 23-year-old woman in 2021, the outlet reported after obtaining police records. The first two deaths were tied to ecstasy or molly consumption and the 23-year-old died from effects of MDA, or known as “sally” and methamphetamine.

The Mayor’s Office has defended the venue, with a spokesperson telling Gothamist in March the facility had strong safety protocols that included thorough security checks before entering and providing medical care on site.

The spokesperson also said the NYPD had a “very positive relationship” with the Avant Gardner.