From today's Gun Watch blog by Dean Weingarten. It's short and to the point. Reiterates one of the many shortcomings of the the "security" in place at the school... including knowing of the perpetrator for at least a year before the murders, and seeing him when he first walked into the school with a rifle case... and doing nothing... okay, well, the second security guard when told by the first who saw the murderer enter the school with a rifle case, he hid in a closet until everyone was dead. That's some tactical training kicking in there...
http://gunwatch.blogspot.com/2018/12/more-cowardice-uncovered-at-parkland.htmlMore Cowardice uncovered at Parkland Shooting: "Security" Recognized Shooter with Rifle case, did NothingWikipedia says the murderer was carry a "duffle bag" and a backpack. That is incorrect. The murderer was carrying a black rifle case, not a duffle bag.

Rifle Case used by Mass Murderer in Parkland
It is a critical distinction, because Andrew Medina, a school security monitor, recognized the rifle case.
Andrew Medina stated the murderer was carrying a rifle bag, and he recognized it as such. He said this in a recorded interview, under oath, shortly after the shooting.
Link to interview video on twitter 9https://twitter.com/AndrewPollackFL/status/1069717638803267584?s=03)
He was the first person recorded to see the murderer enter campus. He stated that he had been briefed; the murderer was the most likely to "shoot up the school" and that he recognized him. From the miami herald.com:
As soon as Cruz began walking "like on a mission" toward the building, Medina followed and began frantically texting fellow security guards. "We had a meeting about him last year and we said if there's gonna be anybody whose gonna come to this school and shoot this school up, it's going to be that kid," Medina told detectives on the day of the Feb. 14 shooting.
Medina stated that when the murderer had been enrolled at the school they were "always watching him":
"Just crazy," Medina recalled of Cruz during the teen's time at Parkland. "And we always was watching him, you know. Like, it was one of those kids that we always kept an eye on."
What was the point of being briefed on the threat, recognizing him, and then doing nothing to stop him? Medina called another unarmed security monitor. That monitor hid in a closet during the shooting.
This is an obvious point of failure of the system. If Medina had confronted the murderer, he might have been able to stop him from entering the school. At the minumum, he would have disrupted the murderers plan and reduced the response time by armed police.
Medina recognized him as a threat. He recognized he was carrying a rifle case. The murderer was forbidden from being on the school campus. A rifle in a rifle case is not an immediate threat until it is removed from the case. The murderer did not appear to be armed with other weapons. Medina did nothing to stop him. He never shouted at him or called for him to stop.
Medina is said, after the shooting started, a minute after the murderer entered the school, to have driven to the front of the school (on his utility vehicle) to get Scot Peterson, the armed school resource officer and Sheriff's deputy. Medina said he took Peterson back to where the murderer entered the school.
That is where Peterson stayed, calling backup, and waiting.