Here's What We Know About The South Florida School Shooting So Far

Tragedy unfolded when a gunman entered a high school in Parkland, Florida, on Wednesday and opened fire, killing 17 people and injuring 15 others.

Students and faculty ran for cover, hiding in closets and under desks. Law enforcement checked the multiple buildings at Marjory Stoneman Douglas High School while lockdown procedures were in place, then slowly evacuated those inside while searching for the gunman.

A 19-year-old former student, Nikolas Cruz, was arrested more than an hour after the rampage began.

This is what we know about the shooting.

Three Minutes Of Gunfire

The gunman reportedly arrived at the high school at 2:19 p.m. by using Uber , then entered the east stairwell of the schools Building 12. He had an AR-15 assault-style rifle in a black case as well as multiple magazines of ammunition, according to Broward County Sheriff Scott Israel.

Sen. Bill Nelson (D-Fla.) said the gunman pulled a fire alarm , which brought students en masse into the hallway. Cruz then opened fire, which alerted the school to initiate its lockdown procedures. Students and faculty members ran for cover to hide from the attack.

Shooting timeline, per sheriff:

2:19 p.m.- Uber drops off suspect
2:21 p.m.- Gunman begins shooting inside school
Gunman exits school, goes to Walmart, buys drink at Subway
3:01 p.m.- Suspect goes to McDonald's
3:41 p.m.- Suspect detained after leaving McDonald's pic.twitter.com/Dnp2xtpxSK

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Shooting timeline, per sheriff:

2:19 p.m.- Uber drops off suspect
2:21 p.m.- Gunman begins shooting inside school
Gunman exits school, goes to Walmart, buys drink at Subway
3:01 p.m.- Suspect goes to McDonald's
3:41 p.m.- Suspect detained after leaving McDonald's pic.twitter.com/Dnp2xtpxSK
NBC News (@NBCNews) February 15, 2018

The shooter began his rampage at 2:21 p.m. by shooting into multiple classrooms on the first floor, according to the sheriffs timeline. He then went to the second floor, shooting a victim in Room 1234, before continuing on to the third floor.

About three minutes after the shooting began, the shooter left his rifle and backpack on the third floor and ran out of the building, exiting about 2:27. Police report that the gunman escaped by blending in with those fleeing the school.

Cruz entered a nearby Walmart at 2:50 p.m., buying a drink at the Subway restaurant inside the store. He then briefly went inside a McDonalds, the sheriffs office said.

An officer from Coconut Creek Police Department detained Cruz at 3:41 p.m., an hour and 20 minutes after the school shooting began.

Three Minutes Of Gunfire

Another Lone Gunman