San Francisco, Mar 28 (IANS): The female shooter who killed 6 people, including 3 children, at a Nashville Christian elementary school, had sent her final, chilling message to her friend on Instagram, saying: "I'm planning to die today".

Mass shooter Audrey Hale, 28, who was shot dead by cops, sent a friend a "suicide note" minutes before slaughtering three children and three adults at the school on Monday.

She messaged Averianna Patton, her former middle school basketball teammate, on Instagram before perpetrating the massacre, reports NewsChannel 5.

"This is my last goodbye. I love youa See you again in another life," posted Hale who has been identified as a transgender.

"You'll probably hear about me on the news after I die," Hale continued.

"So basically that post I made on here about you, that was basically a suicide note. I'm planning to die today," Hale added, using the Instagram name Aiden.

Patton replied: "Audrey! You have so much more life to live. I pray God keeps and covers you."

In response, Hale posted: "I know but I don't want to live. I'm so sorry. I'm not trying to upset you or get attention. I just need to die. I wanted to tell you first because you are the most beautiful person I've ever seen and known all my life."

She added: "My family doesn't know what I'm about to do. One day this will make more sense. I've left more than enough evidence behind. But something bad is about to happen."

Police said she left behind a manifesto and a map that she used to plan the massacre.

The three students who were shot and killed at the Covenant School were all nine years old, according to the Metro Nashville Police Department.

Three adult staff members of the school who also died in the mass shooting were named as 61-year-old Cynthia Peak, 60-year-old Katherine Koonce, and 61-year-old Mike Hill.

The shooter was killed in a shootout with police responding to the incident.