As the search for Brian Thompson's killer continues, experts in NYPD murder manhunts explain why it's taken this long

• The man who shot UnitedHealthcare's CEO appeared to have planned carefully, experts in NYPD manhunts told BI.
• He took key precautions that delayed his capture, they said — including fleeing into Central Park.
• The park is the only part of Manhattan not blanketed by surveillance cameras, they said.

As the search for the killer of UnitedHealthcare CEO Brian Thompson rounds its second full day, the New York Police Department continues to release key evidence in hopes that the public will help.

They've shared crisp, full-color surveillance photos of the suspect and dangled offers of $10,000 for tips leading to his capture. They've described his movements down to the minute, detailing how he stopped at a Starbucks before opening fire on the sidewalk outside the New York Hilton Midtown, then hopped on an electric bike, fleeing into nearby Central Park.

But the ongoing release of information is just a glimpse of what's taking place in the nation's largest police department: a round-the-clock mobilization mixing old-fashioned shoe-leather investigation with high-tech sleuthing.

Two veterans of high-profile, NYPD murder manhunts described these efforts to catch the insurance giant CEO's killer to Business Insider, and said that it's no surprise that he remained at large nearly two days after the shooting.

Both said the shooter appeared to plan carefully— and one raised the possibility that he had professional firearms training.

"First of all, it's a big-ass gun, and the way he's holding it speaks of the military to me — it's clear he knew what he was doing," said Joan Illuzzi, a former homicide prosecutor.

"That — and having his getaway so well-planned — says to me that this is a well-thought-out assassination," said Illuzzi, who was chief of the Manhattan district attorney's trial division before leaving for private practice in 2022.

"He absolutely planned this out," said Salvatore Tudisco, a retired NYPD homicide detective.

Tudisco was chief investigator the last time there was a dayslong manhunt for the killer of a CEO in New York City — millionaire tech founder Fahim Saleh.

Both Illuzzi and Tudisco said they thought the suspect will be identified soon, thanks to the clear surveillance images police have released to the national media.

"That's their best option — send it across the country. Someone will know him," Tudisco said of the photos.

Once he's ID'd, it may take a few days longer to actually apprehend him, the two said.

"To ride into Central Park, that's really bright," said Tudisco. "It's the only blind spot in a city where there's cameras everywhere."

"There are pockets of Central Park that don't have video," Illuzzi said, who is now of counsel at Perry Law in Manhattan.

Thompson's shooter likely had a change of clothing in the gray backpack he wore, Illuzzi said.

As soon as they realized he biked into the park, the NYPD would have dispatched a small army of officers to pull video from the street surveillance cameras surrounding every foot-path and roadway on its perimeter, Tudisco said.

The resulting scouring of surveillance video may have led police to an Upper West Side youth hostel located two blocks west of the park, where the suspect reportedly stayed the night before, Tudisco said.

Many key clues would have stemmed from tracing the shooter's path on the trail of cameras that recorded his movements before and after the shooting, Tudisco said.

A water bottle and burner phone that may have been discarded by the suspect are also reportedly being tested for clues, he said.

Then there are the clues left on the bullet shells themselves. Police said three shells had words written on them. One read "Deny," another "Delay," and the third "Depose."

These could suggest a motive, Illuzzi said. She said it is likely investigators are immersed in scouring litigation records and contested insurance claims for more clues.