The Capitol Hill Massacre

This is pretty terrible. On the evening of Friday, March 24, 2006, a "Better Off Undead" rave was held at the Capitol Hill Arts Center at 1621 12th Ave. The venue had a maximum attendance of 350 people throughout the evening.
Capitol Hill Arts Center
By nearly all accounts, the center itself had excellent security at the event. 
Inside the venue
Sometime between 4 and 6 A.M. Saturday morning, 28 year-old Kyle Aaron Huff left the rave to attend an after party at 2112 E. Republican on Capitol Hill. A last-minute invitee, he didn't know anyone at the party. He was quiet but he still spoke pleasantly with everyone as the party progressed.
Kyle Huff
Nobody recalled him leaving, and there was no altercation or belligerent behavior exhibited by Huff. He left the house and returned to his truck, parked nearby. 
Huff's Truck
From the truck he retrieved a 12-gauge pistol-grip Winchester Defender shotgun and a 40-caliber semiautomatic Ruger handgun, and several bandoliers (over 300 rounds) worth of ammunition for the guns. On his way back to the party, he spray-painted the word "NOW" on the sidewalk and on the steps of a neighboring home.
Steps of neighboring home
Upon arrival, he shot five victims who were outside talking: two on the steps, the others on the porch. He forced his way in through the front door of the house and shot two more people on the first floor. During the shooting Huff allegedly said, "There's plenty for everyone" or something similar.
The scene by 8 AM
On the second floor, he fired through the locked door of a bathroom where a couple had taken refuge inside the bathtub; neither person was hit. At least one other victim was injured during the shooting and taken to Harborview Medical Center, and at least one died at the hospital. The shooting inside the house lasted five minutes. A patrol officer nearby, Steve Leonard, heard the shots and headed to the scene, getting the address from multiple 911 dispatches. When he got to the house, he encountered an injured victim and immediately got between the victim and the house, as Huff was coming down the steps. Before the officer could complete his demand that Huff drop his weapon, Huff put the gun in his mouth and shot himself through the head.
Huff's body is removed
Following the shooting, police found that Huff's truck contained a Bushmaster XM15 E2S rifle, another handgun, several more boxes of ammunition, a baseball bat, and a machete. On Saturday afternoon the Seattle Police Department served a search warrant on the North Seattle apartment that Huff shared with his identical twin brother, Kane.
Huff Brothers' Apartment
They found more guns and ammunition. During the search, Huff's brother returned home, unaware of what had happened. He was taken into custody, questioned, then later released. On March 28, the Church Council of Greater Seattle, led by the Rev. Sanford Brown and other local clergy held an interfaith prayer service at the site of the massacre.
Memorial at Crime Scene
The service was attended by over 500 people. Huff's motives remain unknown. He claimed to have attended The Art Institute of Seattle and North Seattle Community College, although neither institution has any record of him attending. He had previously been arrested in his home town of Whitefish, Montana for destroying a public arts project and was charged with a felony. He shot up a statue of a moose that was part of an installation called "Moose on the Loose." (People, you can't make this stuff up.) He was described by residents there as a well-liked person with a minor history of delinquency. He moved to Seattle with his twin brother about five years before the shooting. He had little contact with police in Seattle, but was involved in a brawl at the Lobo Saloon in 2004. Huff was not well known in Seattle's rave scene. Very few people knew him or interacted with him. On February 1, 2006, someone with the email address asked on an internet message board run by local raver Groovinkim when the next rave was, because he'd never been to one. A possible window into the killer's motives appeared nearly a month after the event. An apartment manager of a complex about a mile from Huff's residence called police about a possible bomb he found while inspecting dumpsters, although that bomb turned out to be just modeling clay and wires. In the investigation afterwards, police found a handwritten note in the dumpster apparently written by Huff. On June 6th, the police released the letter, not yet authenticated, to the media.
Letter to Brother

A week later, the Washington State Crime Lab concluded that it was "highly probable" that the letter was authentic. Arguments in favor of authenticity included the fact that the letter was written on stationery from the apartment complex where the Huff brothers lived, and matched several known samples of the killer's writing, according to crime lab experts. The letter, dated two days before the killings, was quite specific in expressing the writer's anger at young ravers for their provocative lifestyle, particularly their sexual freedom, and said that the things they did and said were too disturbing for the writer to live with. It ended with the quote "Now, kids, Now", reminiscent of the letters "NOW" that Huff spray painted during the massacre. In July 2006, an investigative panel (consisting of old, out of touch, right-wingers) released its findings to the public. In attempting to explain Huff's motivations, the panel suggested that a Nirvana song called "I Want to Know Now", with a chorus refrain of "now, now, now, now" influenced Huff's spray painted message. (Whatever, that pisses me off. Especially since the entire panel admitted they had never heard a Nirvana song) The victims in this tragedy were Melissa Moore, 14; Suzanne Thorne, 15; Justin "Sushi" Schwartz, 22; Christopher "Deacon" Williamson, 21; Jeremy Martin, 26, and Jason Travers, 32. Two other teens were also injured. In the Summer of 2006, a seven sided memorial was built in honor of the victims...and even Kyle Huff.
Temporary Memorial
Six sides were for the people he shot to death and the seventh was a broken mirror. The artist's said viewers could take from it what they want in their own cracked reflection. Most of the dozen or so people involved in the project were part of the Burning Man community, the group with an artistic bent that gathers for an annual festival in the Nevada desert. They are inspired by the temples the artist David Best builds at Burning Man. At the Seattle Center, people were invited to write on the memorial. Then the whole thing was hauled to Burning Man in late August and torched. The house where the shooting took place has been cleaned up, painted, and rented out again. The tenants are aware of where they live and don't mind at all. They say the house is cheerful and doesn't hold any bad vibes. People still visit and drive by the house frequently.
The House Today