Slain after app hookup

A MAN is facing the rest of his life behind bars for knifing a man to death in Brooklyn after meeting him on a gay hook-up app.

The alleged killer, though, had no idea the victim was under investigation for a sex assault.

In April, David Haigh of Pennsylvania traveled to Brooklyn to meet James Johnson in person after hooking up on an online dating and chat app called “Jack’d.”

But Haigh, 42, was unaware that Johnson, 41, was under investigation by the NYPD for criminal sex act charges stemming from an attack on another man nine days before, the Daily News has learned.

On April 9, Haigh and Johnsonwent back to his Fort Greene apartment and at some point, Haigh felt threatened. He admitted to repeatedly stabbing Johnson, according to the criminal complaint.

If convicted, he faces 25 years to life in prison.