The FBI is piecing together what led up to the deadliest mass shooting in U.S. history that killed 49 people and injured 53 others at an Orlando, Florida nightclub.
Agents seized a laptop computer, a Kindle, and cell phones from gunman Omar Mateen's home, and also searched his car.
They say Mateen was a heavy internet user, had a presence on social media, and did not delete his files.
The FBI believes Mateen was radicalized by foreign terrorist organizations but say there is no indication the attack was directed from outside the United States.
Police say all of the victim's bodies have now been removed from the club.
Monday, volunteers wearing red and black t-shirts walked with victims' family members, shielding them from view so they could mourn privately.
Investigators say Mateen used an AR-15 assault rifle and a handgun to carry out Sunday's attack.
A standoff with Mateen ended in a gun battle when the SWAT team punched holes through a wall and stormed the club.
Tulsa police said no one can ever be ready for a situation like what happened in Orlando, but thanks to their training and equipment, they are prepared.
Tulsa's Special Operations Team has 50 members - tactical, negotiators, precision rifle operators and medics - who train twice a month to expect the unexpected, like an active shooter.
They think about it, talk about it and plan for it.
"We do things on a daily basis to prepare," Captain Mike Eckert said.
They have an MRAP and a Saracen, both, big beasts of steel. And the officers are armed with M4s, a fully automatic version of an AR-15.
There was a lot of criticism about this type of equipment recently, but police say the armored vehicles protect officers who must get close to danger.
They also use them to rescue people in natural disasters and hostage situations.
Eckert said, "These vehicles can do things most police vehicles can't, that very few vehicles can. Take 50,000 pounds of steel, put a ram on it and it's the key to the city; you can get into anywhere you need to, and, more importantly, like in Orlando, get people out."
The Special Operations Team has ballistic helmets, but patrol officers do not.
And, ballistic vests they wear do stop handgun rounds; but, when faced with 223 rounds like in Orlando, most vests do not.
So while they do have good equipment and training, police say they could always use more.