Two girls who died in an apparent murder-suicide at an Arizona high school yesterday were reportedly in a romantic relationship.

May Kieu and Dorothy Dutiel, both sophomores at Independence High School in Glendale, died of a single gunshot wound each at about 8am Friday morning.

Their bodies were found just outside the school cafeteria, with a gun nearby.

Police have not said which one teen fired the shots, but a suicide note was found at the scene.

Hours before the shooting, Dorothy tweeted: "Good bye."

Classmates told KPHO that Kieu and Dutiel had been dating for some time, but may have been ending their relationship.

Kieu’s sister, a math teacher at Independence High, says the girls were just friends—though Dutiel wanted something more and was jealous when May spent time with other people.

In December, Dutiel wrote a message on Instagram detailing her view of their relationship:

"This is my lovely babe from a while back. Sadly I don’t have any photos from 2013, but that’s when we begun dating. It started in 6/7th grade when we were friends.

Through like 7th grade we were “best friends” and god I loathed the word. I liked May since 5th grade, a little kid crush I guess. Slowly I began to see what a lovely dork she was.

There was a point where she thought of me as her sister, and the feels were damaged. Along this time frame we both dated, but that doesnt really matter anymore. She was the light of my life, and by 8th grade I knew she was interested.

'But of course both of us were dorks and I was too scared to verbally ask her. So I wrote it on a sticky note and she said yes. That was Nov. 11, 2013.

'We graduated from 8th grade together, and fearfully entered freshmen year. We had little hard ships along the way but we both grew from them.

'Life seemed to get a little better and she was still there. I couldn’t believe she was still there, holding my hand.'

A candlelight vigil is being held at the school tonight.