The manhunt for the cold-blooded assassin who gunned down UnitedHealthCare CEO Brian Thompson in Midtown entered its second day Thursday — and investigators have no shortage of clues.
Beyond the chilling first image showing the masked suspect’s face — in which he grins widely — NYPD detectives and FBI agents ran down leads and processed a trail of evidence they hope will lead to still-unidentified killer.
Here are the major clues:
A rare World War II spy gun
The killer may have used a modern version of a rare World War II spy gun, and investigators hope to track down its purchase, sources told The Post.
The gun used by the shooter in the slaying outside the Hilton hotel on Sixth Avenue appears to be a B&T VP9, an update of the Welrod pistol — a suppressed firearm developed in the Second World War, sources said.
A recent purchase of that gun by a Connecticut-based gunmaker was an investigative lead in the manhunt, according to sources.
But the killer’s gun had still not been recovered nearly two days after the shooting, making the link less than definitive.
Disturbing surveillance video depicting the shooting showed the gunman use a pistol with a silencer, racking its slide seemingly expertly with each shot.
An Upper West Side hostel
Investigators tracking the suspected killer’s path through Manhattan were led to the HI New York City Hostel along Amsterdam Avenue on the Upper West Side, sources said.
The surveillance image showing the suspect’s full, smiling face were taken in the hostel, the sources said.
A swarm of plainclothes NYPD cops and FBI agents searched the hostel Wednesday, residents told The Post.
The suspect appears to have used a fake New Jersey ID to check into the hostel on Nov. 30, sources said.
But investigators also found signs the killer had been in New York City since Nov. 24, though it’s unclear where he was staying before he checked into the hostel, according to sources.
Search continues for killer’s getaway electric bicycle, backpack
The electric bicycle that the gunman rode up Sixth Avenue and into Central Park after coolly slaughtering Thompson at around 6:46 a.m. still remained missing Thursday.
NYPD officials originally identified the killer’s ride as a Citi Bike, but representatives from parent company Lyft later said that police confirmed they no longer believe the suspect used one of their bicycles.
A law-enforcement source said the suspect may have taken the subway from the hostel, carrying a backpack with a battery for the bike.
Video that emerged Thursday showed the suspect casually strolling out of what appears to be the 57th Street subway station in Midtown about 30 minutes before the shooting.
The suspect wears a distinctive gray backpack in the video, as well as other footage from the shooting itself.
But sources said other video footage showing the suspect leave Central Park at West 77th Street without the backpack — which prompted a massive search for the pack Wednesday that was unsuccessful.
Burner phone, water bottle and fingerprints
Police continued to scour a so-called burner phone — a prepaid cellphone without contracts, making it hard to trace — that was found in an alleyway near the shooting scene.
Fingerprints were recovered as police processed both the phone and a water bottle found nearby, sources said.
The suspect was seen making a call on a phone as he made his way to the Hilton Hotel on Sixth Avenue about 10 minutes before the murder.
Officials believe the water bottle is one of two that he purchased at a Starbucks on West 56th Street and Sixth Avenue, located just a few minutes’ walk from the hotel.
— Additional reporting by Ronny Reyes