Entry. >> reporter: officer rex engelbert was joint inside the school by several others, including detective mike collazo. >> once we started hearing the first off, that is and everything kicked into overdrive for us. >> we continued to hear more shots being fired. >> reporter: the police chief says some of the officers had never met, but instead they worked as a team, with little regard for their safety. >> they formed together, they got prepared, and went right in. >> reporter: and today, police released a search warrant, revealing what was seized from the shooter's home. more than 47 items,...