"Right off the bat, this guy had a day to get away," Alcazar told NBC News.
They probably already have a lot more information about him than they are letting on to the public.".
"That might be the lead the NYPD needs," retired NYPD Detective Jillian Snider told MSNBC.
He also didn't rule out that the killer might still be in New York City.
NYPD Chief of Detectives Joseph Kenny said later they believed the suspect had left New York City.
Thompson's final moments were caught on surveillance camera footage, which showed the gunman approaching him from behind and opening fire.
Alcazar said the fact that no murder weapon has been found might, in and of itself, also be a clue. »