The suspect in the shooting of UnitedHealthcare CEO Brian Thompson is fighting extradition from Pennsylvania, but sources tell ABC News that prosecutors at the Manhattan DA's office have started presenting evidence to a grand jury.
An indictment could strengthen the case for extradition, which Luigi Mangione, 26, is fighting.
Manhattan District Attorney Alvin Bragg would not discuss the evidence in detail, but he did express confidence in the case he is building.
"This this is obviously a profound, profoundly disturbing as we've alleged murder," Bragg said. "We would not charge the person if we didn't think it was the person and we're prepared to go forward."
Gov. Kathy Hochul said she expects an extradition warrant "will be issued any day now," which she will sign "the second that happens" and then work with Pennsylvania Gov Josh Shapiro to get Mangione extradited to New York as quickly as possible.
"I want to get him back here in the state of New York and run him through our criminal justice system, because that horrific attack occurred on our streets and the people of our city deserve to have that sense of calm that this perpetrator has been caught and will never see the light of day if there is justice," Hochul said. "You cannot assassinate an individual on the streets of New York, not now, not ever."
The Ivy League graduate remains locked up in a Pennsylvania state prison after a judge denied bail Tuesday.
Mangione was apprehended in Altoona, Pennsylvania, on Monday after nearly one week on the run following the Dec. 4 slaying.
The evidence includes fingerprints lifted from a water bottle and granola bar wrapper found in Midtown. Police say they match the prints taken from Mangione after his arrest in Altoona.
Additionally, the NYPD says ballistics from the ghost gun that Mangione was carrying match three shell casings recovered from the crime scene.
Authorities also say Mangione was also carrying writings linking him to the slaying.
In Pennsylvania, Mangione faces charges including allegedly possessing an untraceable ghost gun.
In New York, he faces charges including second-degree murder.
ABC News asked Bragg why Mangione is facing a charge of second-degree murder and it appears to be a quirk of the way the statute is written in New York.
He says first-degree murder is reserved for special categories like baby killers, cop killers and serial killers, but the DA did leave open the possibility if they learn more, there could be additional charges.
