The man who allegedly placed an unhinged straphanger in a deadly chokehold on a Lower Manhattan train has been released without charges, cops said Tuesday morning. 

A 30-year-old man had been acting erratically and threatening passengers on board a northbound F train just before 2:30 p.m. Monday when another rider intervened to stop him, police said. 

That passenger, 24, put the disruptive man in a headlock, cops said. 

He lost consciousness and EMS workers at the Broadway–Lafayette Street/Bleecker Street station were unable to revive him, cops said.

The younger man was initially taken into police custody, but the NYPD confirmed Tuesday morning that he was cut loose. 

The man who died was not identified early Tuesday, pending family notification. 

He had numerous prior arrests for offenses including assault, disorderly conduct, and fare beating, law enforcement sources said.