Nashville school shooting: Timeline of events leading up to attack that killed 6

NASHVILLE, Tenn. -- Three children and three adults at the Covenant School in Nashville were shot and killed Monday morning. Responding officers shot and killed the suspect -- identified as Audrey Hale, 28 -- about 14 minutes after the initial 911 call came in, according to the Metropolitan Nashville Police Department.

Here's a timeline of events leading up to the deadly attack, according to law enforcement's investigation:

9:53 a.m.: Audrey Hale's vehicle, a grey Honda Fit, is seen on surveillance cameras arriving at the Covenant School and parking in the lot. Police would later find writings relevant to the shooting and diagrams of the school in the vehicle, authorities said.

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9:57 a.m.: Hale sends an Instagram message to an acquaintance, Paige Patton. The two played basketball together in eighth grade and remained in occasional contact, Patton told ABC News.

Hale wrote, "I'm planning to die today. This is not a joke. You will probably hear about me on the news after I die." Hale would later write, "Something bad is about to happen ... Forgive me."

10:10 a.m.: The suspected shooter is seen in surveillance footage shooting through a glass door and entering the building. Officials said this initial barrage of gunfire through the glass door killed a custodian who had been standing in the hallway. Hale was armed with two assault-type guns and a 9-millimeter pistol.

Over the next 13 minutes, the shooter would go on to kill six people in sum, including three students. At some point, Hale made it to the second floor, where they fired from a large glass window down onto responding officers, officials said.

10:13 a.m.: Nashville Police received the first call of an active shooter inside Covenant School, authorities said.

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10:13 a.m.: Hale passed by the church office, according to law enforcement officials.

10:20 a.m.: Hale walked past the children's ministry, according to law enforcement officials.

10:21 a.m.: The first responding officers arrived on campus, law enforcement officials said.

10:23 a.m.: The first law enforcement officers entered the school, according to investigators. Police body-worn camera footage shows officers meticulously going room-to-room looking for the shooter, clearing classrooms and speeding past at least one body in a hallway.

10:24 a.m.: A team of five officers arrived on the second level and followed the sound of gunfire toward the shooter, as seen on police body-worn camera made public on Tuesday.

10:25 a.m.: Two officers engaged the suspect, and the suspect is reported down, according to law enforcement officials.

10:27 a.m.: The suspected shooter is declared dead, investigators said.

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