Two teenagers at a Glendale high school were killed Friday morning in what police are calling a murder-suicide.

Glendale police spokesperson Tracey Breeden said officers responded to calls of a shooting at Independence High School near 75th and Glendale avenues just before 8 a.m., right around the time school was scheduled to begin for the day.

.@GlendaleAZPD responded to Independence H.S. in less than two minutes and found two 15-year-old, female students dead on scene. @abc15 — Anthony Cave (@Anthony_Cave) February 12, 2016

WHAT HAPPENED?

Police found two 15-year-old female sophomores lying next to each other on campus, each dead from a single gunshot wound, said Breeden. A weapon was found next to them.

Breeden said a suicide note was also located at the scene, leading detectives to believe one of the teens shot the other before turning the gun on herself.

Teacher Phuong Kieu talked to ABC15 Friday afternoon and identified her sister May as one of the victims. Police have not yet confirmed the victims' identities.

RELATED: Sister speaks out about teen killed in shooting

According to Breeden, the investigation has revealed the two girls were very close friends and appeared to also be in a relationship.

Police referred to the situation as an "isolated incident," and were quick to reassure parents that their children "are safe" and that this was not an active shooter-type situation.

Students hugging, crying after leaving Independence High @abc15 pic.twitter.com/BSHjjoHVd7 — Nick Ciletti (@NickCiletti) February 12, 2016

Detectives say they are not looking for any other suspects or persons of interest.

One student says she was shocked to learn that two teens died in a shooting at her school.

Senior Lanie Walter said Friday that the shooting was heartbreaking because "everyone is so loving" at Independence High School.

She says she heard ambulances on her way to the campus in Glendale but didn't think much of it until her first class went on lockdown.

75th Ave and Bethany Home. Road closed. Just spoke to mom who finally heard from son. @abc15 pic.twitter.com/DGpWlMFI0m — Nick Ciletti (@NickCiletti) February 12, 2016

She called her parents to tell them she was OK and said her mother was relieved because she had been watching the news.

The principal of Independence High School sent a letter to parents which reads:

It is with a heavy heart I inform you that a tragedy occurred at Independence High School today. Before the start of school today, two female students lost their lives while on campus.

The school was immediately placed in lock down and the Glendale Police Department responded quickly, assessing the safety of our students, faculty and staff.

The Glendale Police Department secured the scene and immediately began their investigation. We are working in partnership with the police department as the investigation continues.

As stated in the media press conference, this tragedy was an isolated incident. There was never an active shooter on campus and police are not searching for a suspect.

Our hearts and minds are with the families who lost their children today. We offer our deepest condolences. As an Independence community we will support the families and each other. We will be providing a team of social workers for our students and families tomorrow (Saturday, February 13). They will be available from 9 a.m. to noon in the Media Center. As well, the team will be available to support students when they return to school on Tuesday.

We thank you for your support and understanding as our community deals with this tragedy.

Glendale Union High School District: "Our hearts and thoughts are with the families affected by this tragedy." pic.twitter.com/C1uDexmEFi — ABC15 Arizona (@abc15) February 12, 2016

ABC15 reached Glendale Vice Mayor Ian Hugh by phone Friday. He called the shooting "a horrible tragedy" and said that city employees are following the developments.

Nearby 75th Avenue was closed between Glendale Avenue and Bethany Home Road while police worked to clear the scene. The road was reopened around 2:30 p.m.

GOV. DOUG DUCEY: 'OUR HEARTS REMAIN WITH THE STUDENTS, EDUCATORS AND FAMILIES'

Gov. Doug Ducey released the following statement as new information was released.

"As details of this morning's tragic shooting continue to be released, our hearts remain with the students, educators and families of Independence High School and the entire Glendale community."

He thanked first responders, police, teachers and school administrators for their "swift response and diligent work" to keep the area safe.

"Our thoughts and prayers are with them, with everyone on scene and with the community during this difficult time," his statement read.

Independence High School is part of the Glendale Union High School District. It joined the district in 1977, according to the school's website.

GUHSD has nine high schools that cater to 15,000 students in Phoenix and Glendale, according to its website.

INFOGRAPHIC: A LOOK AT SCHOOL SHOOTINGS IN 2016