Police appeared to be closing on the identity of the assassin who gunned down the UnitedHealthcare CEO in midtown Manhattan Thursday as they released a photo of the grinning suspect and looked into a gun purchase in Connecticut.

The photos, shared by the NYPD on X, show the “person of interest,” who is wearing a similar outfit as in earlier photos of the shooter, with his face mask down.

The development came as law enforcement sources told the New York Times that they were investigating the purchase of a gun in Connecticut that resembled the one used in the killing outside of the New York Hilton early Wednesday.

The gun appears to be a B&T VP9, an update of the Welrod pistol — a suppressed firearm developed in the Second World War, sources told the New York Post .

Police on Wednesday also searched the HI NYC Hostel on 103rd and Amsterdam Avenue, where the suspected killer is believed to have stayed in a room with two other men, according to CNN.

Matheus Taranto, who was staying at the hostel while visiting from Brazil, told the Daily Beast that police swept through the building around 5 or 6 p.m. and seemed particularly interested in room 407, which remained locked Thursday.

“I was going to the bathroom, and [a police officer] was like, No, you can’t pass here,” Taranto said.

Although sources told CNN that the suspect largely wore a mask while he was at the Upper West Side hostel, police were able to obtain one image of the man from his stay in which his face is visible.

The NYPD declined to comment on the hostel search.

The latest developments in the race to apprehend the killer, who stalked Thompson outside his hotel before firing several shots at close range, comes as law enforcement is closing in on the suspect’s identity, police sources told ABC News .

Investigators have several possible suspect names, but they were inconclusive when compared to the surveillance image released Thursday, a law enforcement official told the New York Times .

Cops also retrieved a fingerprint from a water bottle the suspect dropped while fleeing the crime scene Wednesday morning. Law enforcement officials told CNN the fingerprint lifted from the bottle seems to be smudged, making it less conclusive.

Thompson was in the city for an investor conference for his firm, one of the largest health insurance companies in America.

After using a silenced weapon to gun the executive down in what city police commissioner Jessica Tisch called a “premeditated, pre-planned, targeted attack,” the killer fled on an electric bike, kicking off a sprawling manhunt.

While the killer’s motive remains unknown, the investigation has so far turned up a number of clues.

The police found bullet casings at the scene with the words “deny,” “defend,” and “depose” engraved on them, ABC News reported Wednesday night.

CCTV footage from around the crime scene shows the suspect wearing a brown jacket, a black face mask, and a gray backpack.

Items believed to have belonged to the shooter, including a water bottle and a candy wrapper, were recovered from the alley in which he fled the scene of the attack.

Thompson’s wife revealed to NBC News that Thompson had received “some threats” related to “lack of coverage” before he was slain.