Shooting suspect knew guns 'inside and out'

The day before 17 people were gunned down at a Florida school, a co-worker says the suspect made plans to go with him to a shooting range.

Brian Halem tells the Miami Herald he asked 19-year-old Nikolas Cruz for his phone number last Tuesday so they could coordinate a weekend trip to Gun World of South Florida. "Save it as, `Crazy Nick,"' Cruz told his new friend.

Halem, a 19-year-old college freshman, worked with Cruz at the Dollar Tree in Parkland and says they bonded over enthusiasm for firearms. He describes Cruz -- now charged with 17 counts of premeditated murder -- as a "walking dictionary" who "knew guns inside and out."

In hindsight, Halem says conversations about tactics like wearing a gas mask during a firefight might have been a red flag. But Halem says he was shocked by the shootings.