A 16-year-old girl opened fire on a primary school on January 29, 1979, injuring eight children and killing two adults.

Brenda Spencer’s home in San Diego was directly across the road from Grover Cleveland Elementary School.

As students lined up outside the school at the start of the day waiting for the principal to open the gate, she opened fire with a semi-automatic rifle.

Brenda Spencer was just 16 when she opened fire on a line of school children. (Nine Archives)

With 36 shots fired from her home, she killed the school principal and a custodian who were rushing to pull students to safety.

Eight children were shot, as well as a police officer wounded in the neck. All survived.

Spencer then barricaded herself in her home.

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As police negotiators waited outside, she answered a phone call.

A reporter from local paper the Evening Tribune had been cold-calling random telephone numbers in the neighbourhood to speak to potential witnesses.

When the reporter realised who he had on the phone, he asked her why she had done what she had done.

16-year-old Brenda Spencer was tried as an adult after her massacre. (Bettmann Archive)

“I don’t like Mondays,” she replied.

“This livens up the day.”

For six hours, police were in a standoff with Spencer.

She eventually surrendered after being promised a Burger King meal.

Though still a minor, she was tried as an adult on murder charges.

While awaiting trial, one of her cellmates later began a relationship with Spencer’s father upon her release. They later married and divorced.

The day after her 18th birthday, Spencer was sentenced to life behind bars.

Spencer was denied parole for the seventh time last year.

Brenda Spencer has been in prison since the massacre. (Getty)

“The shock of this brazen crime rippled through the community in San Diego at the time and it continues to hold a place of infamy in the history of mass shootings in our nation,” district attorney Summer Stephan said.

“While new laws are in place that can potentially speed up releases for individuals who were convicted as minors, as well as inmates who are over 50 years old, our position is that the totality of the horrific circumstances of this crime and this case do not warrant release and we are gratified that the parole board agreed with our position.”

She will be eligible for parole again in 2028.

Six months after the shooting, Irish pop band The Boomtown Rats released the song I Don’t Like Mondays, inspired by the shooting.

It was a massive hit in Ireland and the UK, but radio stations in San Diego refused to play the song.

Johnnie Fingers, Bob Geldof and Garry Roberts (bottom) Gerry Cott, Simon Crowe and Pete Briquette of the Boomtown Rats in October 1979. (Photo by Fin Costello/Redferns) (Redferns)

“She wrote to me saying she was glad she’d done it because I’d made her famous,” lead singer Bob Geldof later said in an interview.

“Which is not a good thing to live with.”