Obscure shootings

I've got a fairly detailed spreadsheet, and it has most mass shootings listed on it, but i'm wondering if anyone here knows of any particularly obscure mass shootings that i may have missed or overlooked.

I am specifically referring to mass shootings, not mass killings in general.

1938 Turkey shooting - a man shot and killed 26 people and wounded an unspecified numbers of others before being shot.

Verlin Spencer. He was a principal who shot up the school he worked at Steinhäuser-style, killing five other members of its faculty, before botching his own suicide and spending three decades in prison. He was later found to have been on so much bromide that he could have been declared legally insane, but he never got a retrial.

The reason he's so obscure is because his case is so old. It happened in 1940, nearly a decade before even Unruh.

He also got parole (hence 'only' three decades in prison) under the condition that he leave the state of California, where the shooting happened, and moved to Hawaii. Can't see that happening to a school shooter with 5 kills nowadays.

Olean High School Shooting - Anthony Barbaro killed three and injured eleven before being arrested and committing suicide in jail
Brampton Centennial Secondary School Shooting - Michael Slobodian killed two and injured thirteen before committing suicide
St. Pius X High School Shooting - Robert Poulin killed two and injured another five before committing suicide
All of this shootings happened in the mid-70s and very little information is available on them due to them being nearly 50 years old.

Monkseaton in 1989. The perpertrator was mentally ill civil servant Robert Sartin.

El Cabanyal Shooting: In february 7, 2000, Ramon Tatay Zanon killed 4 in Valencia Spain, caused a gas explosion in his house, then waited for the Police and the Firemen and killed 3 officers, 1 fireman and a Neighbor with a shotgun in his terrace, finally he was killed by the police