Authorities are still looking for a motive in the worst mass shooting in U.S. history.
Contact 13 Chief Investigator Darcy Spears is here to explain why they're having so much trouble figuring that out.
The problem is how to get inside the mind of a madman. ABC news is reporting that investigators increasingly believe Stephen Paddock suffered from severe but undiagnosed mental illness.
They're seeing a picture of a loner who carefully planned the massacre while the people closest to him didn't notice any red flags.
Investigators have asked the Clark Coroner Coroner to expedite studies of paddock's brain to determine if they could find some sort of anomaly that would indicate a psychiatric disorder.
Detectives found a bottle of prescription Valium in Paddock's hotel room. And now they want to know if he had other prescriptions and if he took them as prescribed.
We've learned Paddock's computer is on it's way to an FBI lab as investigators continue to look for anything that could explain what contributed to this horrific crime.
Doctor Jen Ashton tells ABC News we need to be careful not to stigmatize those dealing with mental illness as they are more likely to be a victims of crime than violent individuals. In Paddock's case, she says his behavior, appearance and actions are classic for someone who is psychiatrically 'disorganized' and having what's termed a 'psychotic break'."