Investigators in Nevada continue to dig for a motive following what's being called the largest mass shooting in modern U.S. history.
Every piece of evidence collected will paint a bigger picture of what happened on the Las Vegas strip where 58 people were killed.
Dr. Henry Lee has worked on 8,000 cases in 46 countries.
"Everyone is puzzled about this motive," Lee said.
Lee is known for finding the tiniest clues which can lead to the biggest discoveries.
"[They] look at the crime scene, look at physical evidence, look at witnesses, look at information, intelligence [and] try to put [it] together," he said.
Lee said he hasn't been asked to consult in Vegas.
However, he said looking at it from the outside, the case comes with challenges like an unclear timeline and a massive amount of evidence to analyze in two crime scenes.
"The room, that’s a separate crime scene," Lee said. "The cop has to preserve the crime scene try to avoid contamination."
Lee said the gunman doesn't really fit the profile of a mass killer. He's older than most of them and didn't set off red flags beforehand.
"If I’m the investigator, I’m going to look at the financial aspect, why he picked that location," Lee said. "[He] must have a reason."
Finding that reason could be the key to answering the questions everyone has been asking.
Lee said he's retired and is only consulting on a few cold cases while continuing some work at the University of New Haven's Institute of Forensic Science, which he founded.
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