Tragedy struck Oxford High School in Michigan Tuesday when a shooting left four students dead and seven others, including one teacher, injured. 

"I just left Oxford high school after a detailed walk-through and examination of the scene and evidence. As I reflect on the day, it is one that is filled with overwhelming sadness. My heart aches for families that will never be the same and a quiet sweet community that had its innocence shattered. I have seen far too many bodies and death in my career, but children’s are always the worst," Oakland County Sheriff Michael Bouchard said according to a Facebook post from the sheriff’s office early Wednesday morning. 

At about 12:51 p.m. on Tuesday, a 15-year-old suspect began shooting in an area of the school where many classes take place, according to police. Oakland County Undersheriff Mike McCabe said police received more than 100 emergency calls and the suspect was in police custody within five minutes of police receiving the first call. 

MICHIGAN HIGH SCHOOL TEEN KILLED IN SHOOTING WAS 'HERO', CLASSMATES SAY

"I was in my biology room, just like laughing with a couple of my friends, and, just like a normal day. And then I hear gunshots coming from close by — and my mood just switched. I went from laughing to crying in about a second," one student, Alysse Avey, told the New York Times. 

Nov 30, 2021; Oxford, MI, USA; Parents walk away with their kids from the Meijer's parking lot in Oxford where many students gathered following an active shooter situation at Oxford High School in Oxford on November 30, 2021.  Mandatory Credit: Eric Seals-USA TODAY NETWORK (Eric Seals-USA TODAY NETWORK)

"We just got in the corner, and sat down exactly how we were supposed to — like we followed the protocols that we practiced, and everyone followed. No one talked, we didn’t scream or anything, we were just silent," Avey added. 

The shooting left four students dead. Three of the victims have been identified as 16-year-old Tate Myre, 14-year-old Hana St. Juliana, and 17-year-old Madisyn Baldwin. 

A fourth student, a 15-year-old boy, died Wednesday, according to authorities. He was identified as Justin Shilling. 

MICHIGAN HIGH SCHOOL SHOOTING LEAVES THREE STUDENTS DEAD; 15-YEAR-OLD SUSPECT IN CUSTODY

Myre has been described as a "standout" football player who died in the back of a patrol car as deputies rushed him to a hospital. 

Shooting reported at school in Oxford, Michigan (WJBK)

A petition, which has over 36,000 signatures as of Wednesday morning, was started on Tuesday to rename the school’s Wildcat Stadium after Myre. His peers and others lauded him in the comment section of the petition as a hero who was also the "face of Oxford Football."

"Tate was a wonderful young man who was tremendously hardworking and respectful," the Oxford Wildcats football team also tweeted following his death.

Madisyn Baldwin was a senior at the school who was expected to graduate this school year and had just been accepted to a handful of colleges, including with full scholarship. She was the eldest of three siblings and was an artist who enjoyed drawing, writing and reading, according to her family. 

"This kind of thing can happen anywhere and sadly it happened even in a sweet quiet community like Oxford," Bouchard said at a press conference on Tuesday. 

A total of seven people, including students and a teacher, were also injured in the attack, with at least one in critical condition. 

SHOOTING AT MICHIGAN HIGH SCHOOL KILLS THREE AND INJURES EIGHT

A 17-year-old girl is in critical condition after she was shot in the chest. 

A 14-year-old boy is in serious condition with a gunshot wound to the head and jaw. Another 14-year-old boy is on a ventilator after suffering chest and neck wounds. The 47-year-old teacher was grazed by a bullet. 

The unidentified suspect is in police custody and has invoked his right to remain silent. A motive for the attack is unclear. 

"There was no resistance during the arrest and the suspect has asked for a lawyer and has not made any statements as to a motive," the sheriff’s office said on Facebook Tuesday.

Nov 30, 2021; Oxford, MI, USA; Police cars line up in front of the school following an active shooter situation at Oxford High School in Oxford on November 30, 2021. Mandatory Credit: Liz Shepard-USA TODAY NETWORK (Liz Shepard-USA TODAY NETWORK)

Police say the 15-year-old used his father’s gun in the attack, which was only purchased on Nov. 26. 

"A search warrant was executed at the suspect's residence and is being inventoried. The firearm used was a 9mm Sig Sauer and had been purchased by the father four days prior to the incident. There was no prior information shared with the Sheriff's Office or the School Resource Officer before the incident," the sheriff’s office wrote in an update on Facebook. 

Sheriff Bouchard added in his statement Wednesday morning that police worked through the night and will continue their investigation Wednesday. 

"I am super proud of our team as they continue to work through the night and I know the work they did this day saved lives. It is also evident from the scene that the lockdown protocols, training and equipment Oxford schools had in place saved lives as well. I will close this day with more prayers,  as we will be back at it in a couple of hours," he said. 

Oxford High School is closed for the remainder of the week. 

Michigan Democratic Gov. Gretchen Whitmer ordered Michigan and American flags to fly at half-staff at public buildings and grounds in the state following the tragedy. Private businesses, residents and others are also encouraged to lower their flags

"My heart breaks for the students, teachers, staff, and families of Oxford High School," Whitmer said of the tragedy. "The death of multiple students and the shooting of many others, including a teacher, is horrific.

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"I want to thank the first responders on the ground working hard to keep people safe as law enforcement officials investigate this shooting and get the community the help it needs right now. Our state is in mourning alongside the parents who had their children taken from them today and the entire community in Oxford."