The teenager accused of the Georgia high school shooting was enrolled two weeks late and was often absent

ATLANTA (AP) — The 14-year-old accused of killing four people in a Sept. 4 shooting at Apalachee High School in Georgia arrived late for school two weeks and then missed nine more days before the shooting, investigators said Friday.

Colt Gray was first enrolled at the high school northeast of Atlanta on Aug. 14, the Georgia Bureau of Investigation said. The first day of school was Aug. 1.

The late enrollment and absence from class show that the boy's life may have been troubled. His mother, Marcee Gray, said she and other relatives on her side had sought help from the school in the week before the shooting to get mental health treatment for her son.

Colt Gray is charged as an adult with four counts of murder, and District Attorney Brad Smith has said he will likely face additional charges in connection with the wounded. Authorities have also filed charges against his father, Colin Gray, alleging he gave his son access to the gun even though he knew or should have known the teenager posed a danger to himself and others.

Here is a timeline of events before, during and after the attack, based on statements from authorities and reports from The Associated Press and other news media:

August 1 – School starts in Barrow County.

August 14 – Colt Gray attends Apalachee High School. Investigators say he was absent for nine more days before the shooting.

September 4, 8:15 a.m. – First period begins. Officials have not said what class Gray was scheduled for or if he attended. Officials said he rode the school bus to Apalachee High School and had a semi-automatic assault rifle hidden in his backpack. Investigators say Gray also had a knife.

September 4, 9:38 a.m. – The first period is over. Students have seven minutes to move on to the next class.

September 4, 9:45 a.m. – Second period begins. Student Lyela Sayarath said she saw Gray briefly in algebra class, where the two were sitting next to each other. Investigators say Gray left the classroom and asked to speak to someone in the vestibule, but instead he took his backpack with the gun inside and hid in a bathroom.

September 4, 9:50 a.m. – Marcee Gray, Colt's mother, calls the high school from 200 miles away in Fitzgerald, Georgia, to warn that her son was having an “extreme emergency” after receiving a text message from Colt saying “I'm sorry.” Marcee Gray said a teacher told her that one of Colt Gray's teachers had sent an email that morning claiming to have talked about school shootings. Marcee Gray said she urged her to find her son to check on him. Call logs show the conversation lasted until 10 a.m.

Sept. 4, 9:45 a.m. to 10:20 a.m. – An administrator comes into the algebra classroom looking for a student with the same last name and a similar first name as Colt Gray, Sayarath and Barrow County Sheriff Jud Smith said. When the other student returns, he tells Sayarath that the administrator was actually looking for Colt Gray. Meanwhile, the teacher is called over the intercom, Sayarath said.

Sept. 4, about 10:20 a.m. – Colt Gray approaches the algebra classroom door. When the intercom buzzes again, the teacher responds, “Oh, he's here,” when he sees Gray outside the classroom door, Sayarath said. As students move to open the door, which automatically locks from the inside when it's closed, they back away, Sayarath said. She said she saw Gray turn away through the window in the door and then heard 10 or 15 consecutive gunshots. People are shot in the hallway and in at least one classroom, while others run for their lives in the halls. According to some students, the three teachers who were shot are trying to protect the students.

September 4, 10:23 a.m. – After several staff members press wireless panic buttons in their employee badges, the school is locked down and a massive police response begins. Students from other classrooms who hear the gunshots begin texting and calling their parents and others.

September 4, 10:26 a.m. – Two Apalachee High School security officers approach Gray in the hallway, according to GBI Director Chris Hosey. Gray immediately surrenders and is taken into custody.

September 4, around 11 a.m. – Police officers begin searching the home of Colin and Colt Gray east of Winder. At the school, officers go from classroom to classroom, initially looking for other injured people or other shooters. Later, officers evacuate students to the football field as hundreds of parents rush to the campus.

September 4, approximately 1 p.m. – The school begins handing over students to their parents so they can take them home.

September 5 – Colin Gray, the 54-year-old father of Colt Gray, is charged with four counts of manslaughter, two counts of second-degree murder and eight counts of child abuse. Officials say Colin Gray gave Colt Gray access to the assault rifle even though Colin Gray knew his son was a danger to himself or others.

September 6 – Colt and Colin Gray make their first court appearance in Winder. Neither requests that the judge set bail. Colt Gray remains in a juvenile detention center while Colin Gray is in the Barrow County Jail.

September 10 – The 13,000 students at other schools in the Barrow County School District return to class. Officials have not yet announced a date for the resumption of classes for the 1,900 students at the Apalachee school.

September 11 – Colin Gray's lawyers ask a judge to order that he be housed separately from other inmates in the Barrow County Jail for his safety, citing “incalculable” threats of violence or murder against him.