The Midtown office shooter fired 47 rounds from his M4-style assault rifle during the rampage, a number that indicates Shane Tamura reloaded his rifle at least once, the NYPD said.
Detectives located 24 spent shell casings and 15 bullet fragments on the 33rd floor, where Julia Hyman was killed and office cleaner Sebije Nelovic said she was shot at.
There were 23 shell casings and 13 bullet fragments recovered from the lobby of 345 Park Ave.
And 800 additional rounds and a .357 caliber handgun were recovered in Tamura's BMW double parked outside the building, the NYPD said.
Meanwhile the Las Vegas casino security supervisor who sold the assault-style rifle used in Monday's mass shooting complied with the law, his attorney said in a statement.
Tamura, 27, shot and killed four people and then himself using an M4-style rifle he purchased for $1,400 from his supervisor at Horseshoe casino, Rick Ackley, police sources told ABC News.
The sources said it is not clear whether Ackley knew Tamura's intentions when he sold him the gun but he is facing no charges.
"Rick Ackley administered the transfer of the firearm used in the tragedy in New York lawfully complying with Nevada and federal gun laws, Ackley's attorney, Chris Rasmussen, said in a statement.
Police also revealed that during his cross-country drive from Nevada to New York, Tamura received two phone calls.
He received a 31-second call at 7:41 p.m. Sunday while driving through Geneseo, Illinois, and a 59-second call at 5:19 p.m. Monday as he drove through Parsippany, New Jersey, according to police. That call was received about an hour before the shooting.
NYPD detectives have interviewed both people who called the gunman, but declined to discuss the substance of those conversations with Tamura.
It comes as NFL Commissioner Roger Goodell spoke out publicly for the first time since the attack.
He shared information about his visit with the NFL employee who was injured, saying he spent an hour with him in the hospital Thursday. He said he's stable and improving.
Police say the shooter was targeting the NFL headquarters when he entered 345 Park Avenue, but ended up on the wrong floor.
The commissioner was not at Thursday night's game so he could attend the funeral of Detective Didarul Islam.
A vigil for Islam is set for Friday night.
The other victims of the shooting include 43-year-old Blackstone executive Wesley LePatner, 46-year-old security officer Aland Etienne and 27-year-old Rudin Management employee Julia Hyman.
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