The CMU police chief said officers had encountered Davis multiple times in the 24-hours leading up to Friday's shooting.
The person who called an FBI tip line in January said Nikolas Cruz made increasingly alarming statements after his mother died last fall, adding, "I know he's, he's going to explode."
Nikolas Cruz, charged with 17 counts of murder in the Florida school shooting, had stopped off at a Walmart and a McDonald's before authorities tracked him down.
Stephen Mader says he he did nothing wrong in May 2016 when he tried to persuade R.J. Williams, to put down his weapon. Another officer later fatally shot Williams.
The suspect told officers he tried to talk Natalie Bollinger out of killing herself, but she wouldn't budge, according to an affidavit obtained by NBC News.
Salah Abdeslam has previously refused to speak to investigators in France about the attack there that killed 130.
Kyle Brayer, a Marine veteran who had worked with the Tempe Fire Department for 10 years, died after being shot in the head.