Question: Im Not Ashamed is a biographical drama film, based on what massacre involving two American spree killers Eric Harris and Dylan Klebold, who killed 13 people and wounded 24 others? 

Context paragraphs:
The Nobodies (song): "The Nobodies" is a song by American industrial rock band Marilyn Manson.  It is the third and final single from their fourth studio album, "Holy Wood (In the Shadow of the Valley of Death)", released in 2000.  The song addresses Eric Harris and Dylan Klebold, perpetrators of the Columbine High School massacre in 1999.

Eric Harris and Dylan Klebold: Eric David Harris (April 9, 1981 – April 20, 1999) and Dylan Bennet Klebold (September 11, 1981 – April 20, 1999) were two American spree killers and mass murderers who killed 13 people and wounded 24 others armed with firearms and knives on April 20, 1999, at Columbine High School in Columbine, Colorado.  They were twelfth grade (senior) students at the high school.  The shooting rampage came to be known as the Columbine High School massacre.  Harris and Klebold committed suicide in the library, where they had killed 10 of their victims.

Super Columbine Massacre RPG!: Super Columbine Massacre RPG! , abbreviated SCMRPG! , is a role-playing video game created by Danny Ledonne and released in April 2005.  The game recreates the 1999 Columbine High School shootings near Littleton, Colorado.  Players assume the roles of gunmen Eric Harris and Dylan Klebold and act out the massacre, with flashbacks relating parts of Harris and Klebold's past experiences.  The game begins on the day of the shootings and follows Harris and Klebold after their suicides to fictional adventures in perdition.

I'm Not Ashamed: I'm Not Ashamed is a 2016 biographical drama film based on the journals of Rachel Scott, the first victim of the 1999 Columbine High School massacre in Columbine, Colorado.  Scott is the main protagonist, and the story of both gunmen who committed the shooting, Eric Harris and Dylan Klebold, is intertwined with Scott's.

Kumatarō Kido and Yagorō Tani: Kumatarō Kido (城戸 熊太郎 , "Kido Kumatarō" , c.1857–1893) and Yagorō Tani (谷 弥五郎 , "Tani Yagorō" ) were Japanese spree killers who killed 11 people, including an infant, on May 25, 1893, a spree known as Kawachi Jūningiri (河内十人斬り ) .  The roots of the killings were both emotional and financial.  Kido lost his common-law-wife to a man named Torajirō Matsunaga, whose brother, Denjirō, defrauded money from Kido and assaulted him.  Along with a pupil named Tani Yagorō, Kido decided to kill Matsunaga's family.  They prepared guns and swords and on May 25, 1893, they attacked Denjirō's house and killed four people.  They then attacked Denjirō's son's house, killing five people.  They also killed his former common-law-wife and her mother.  However, they were not able to kill Torajirō Matsunaga.  They committed suicide after the murders, and their remains were discovered on June 7.  A novel, "Kokuhaku" by Japanese punk rock singer Kō Machida, was based on their case.

Playing Columbine: Playing Columbine is a 2008 American documentary film produced and edited by Danny Ledonne, an American independent filmmaker.  The film follows the video game "Super Columbine Massacre RPG! " in which players experience the Columbine High School massacre through the eyes of the killers, Eric Harris and Dylan Klebold.

Aramoana massacre: The Aramoana massacre was a spree shooting that occurred on 13 November 1990 in the small seaside township of Aramoana, northeast of Dunedin, New Zealand.  Resident David Gray, after a verbal dispute with his next-door neighbour, killed 13 people, including local police Sergeant Stewart Guthrie, one of the first responders to the reports of a shooting.  After a careful house-by-house search the next day, police officers led by the Anti-Terrorist Squad (now known as the Special Tactics Group) located Gray and shot him dead as he came out of a house firing from the hip.  It is the deadliest criminal shooting in New Zealand history.

Cal Robertson: Cal Robertson (born June 10, 1986) is an American actor.  His most notable performance was that of teenage murderer Cal Gabriel in "Zero Day", a film based on the Columbine High School massacre and perpetrators Eric Harris and Dylan Klebold.  Robertson was cast in the role of Gabriel when director Ben Coccio scouted for actors in Connecticut.  Robertson and co-star Andre Keuck shared Best Actor honors at the 2003 Slamdunk Film Festival.

Columbine (book): Columbine is a non-fiction book written by Dave Cullen and published by Twelve on April 6, 2009.  It is an examination of the Columbine High School massacre, perpetrated by Eric Harris and Dylan Klebold on April 20, 1999.  The book covers two major storylines: the killers' evolution leading up to the attack, and the survivors' struggles with the aftermath over the next decade.  Chapters alternate between the two stories.  Graphic depictions of parts of the attack are included, in addition to the actual names of friends and family (the only exception being the pseudonym "Harriet", which is used for a female Columbine student with whom Klebold was obsessively in love).

Columbine High School massacre: The Columbine High School massacre was a school shooting that occurred on April 20, 1999, at Columbine High School in Columbine, an unincorporated area of Jefferson County in the American state of Colorado.  In addition to the shootings, the complex and highly planned attack involved a fire bomb to divert firefighters, propane tanks converted to bombs placed in the cafeteria, 99 explosive devices, and carbombs.  The perpetrators, senior students Eric Harris and Dylan Klebold, murdered 12 students and one teacher.  They injured 21 additional people, and three more were injured while attempting to escape the school.  The pair subsequently committed suicide.

Supporting paragraphs: I'm Not Ashamed Eric Harris and Dylan Klebold
Answer: 1999 Columbine High School massacre