input: The band released a song called "The Pessimist" as a free download on their Facebook page on March 27, 2012. The song was previously only available on the iTunes deluxe version of the soundtrack to Transformers: Dark of the Moon. They also released their first DVD Live at Brighton in the same year, capturing their performance on November 7, 2010. It was announced via Instagram on May 3, 2012 that bassist Shawn Economaki had parted ways with the band on amicable terms. He was replaced in the studio by current Skid Row bassist Rachel Bolan. Stone Sour started recording their fourth studio album in early 2012. Corey Taylor stated that the album would end up being a double album or concept album, and described the album's sound as "Pink Floyd's The Wall meets Alice in Chains's Dirt". It was later announced that the new material would be released as two separate albums. The first album, House of Gold & Bones - Part 1 was released worldwide on October 23, 2012, and the second album House of Gold & Bones - Part 2 was released worldwide on April 9, 2013. The project also has a 4-part graphic novel series that accompanies the albums, telling the linear storyline featured in the twin albums' lyrics. The first two songs from Part 1, "Gone Sovereign" and the first official single, "Absolute Zero" were released for radio airplay in mid/late August 2012. The first single from House of Gold & Bones Part 2 was "Do Me a Favor". It was released digitally on February 12. Guitarist Josh Rand stated in an interview with O2 Academy that there was a song recorded for Part 1, an instrumental which was deemed 'not up to par' by the band. The song will likely be released in the future once James Root and Josh Rand do 'some stuff to it guitar-wise'. On October 5, 2012, Johny Chow of Fireball Ministry and Cavalera Conspiracy was announced as the bassist for the band on the House of Gold & Bones tour cycle. Stone Sour subsequently played Soundwave Festival 2013 in Australia and on the Sunday at Download Festival 2013. Guitarist James Root did not tour with Stone Sour in the winter of 2013, as he had to take a brief hiatus from the group to work on .5: The Gray Chapter with Slipknot, although it was later revealed that he was fired from the band due to musical differences. He claimed that the band wanted to focus on "radio play and money," in which Root fought against, and that led to a split. Christian Martucci filled in for Root during that period.

Answer this question "Why did Root not tour with the band?"
output: as he had to take a brief hiatus from the group to work on .5: The Gray Chapter with Slipknot, although it was later revealed that he was

Question: Darrell Lance Abbott (August 20, 1966 - December 8, 2004), also known as Dimebag Darrell and Diamond Darrell, was an American musician and songwriter who was a co-founder of Pantera alongside his brother Vinnie Paul, and founder of Damageplan. He was considered to be one of the driving forces behind groove metal. Abbott was shot and killed by a gunman while on stage during a performance with Damageplan on December 8, 2004, at the Alrosa Villa in Columbus, Ohio. He ranked No. 92 in Rolling Stone magazine's 100 Greatest Guitarists and No. 1 in the UK magazine Metal Hammer.

On December 8, 2004, during the Devastation Across The Nation tour, Abbott was shot on-stage while performing with Damageplan at the Alrosa Villa in Columbus, Ohio. A crowd of approximately 250 had watched four support acts (two local bands entitled Volume Dealer and 12 Gauge, and the tour support Shadows Fall and The Haunted). Moments into Damageplan's set, 25-year-old former Marine Nathan Gale shot Abbott five times in the head with a 9 mm Beretta 92F pistol. Some in attendance initially believed the shooting was part of the act, but as Gale continued shooting, the audience quickly came to the realization that the event was not staged. Firing a total of 15 shots, Gale killed three other people and wounded seven more. Jeff "Mayhem" Thompson, the band's head of security, was killed tackling Gale, as was Alrosa Villa employee Erin Halk. Audience member Nathan Bray was killed while trying to perform CPR on Abbott and Thompson. It was rumored that one crowd member leapt in front of the gunman, saving the lives of several band members. Damageplan's drum technician, John "Kat" Brooks, was shot three times as he attempted to disarm Gale, but was overpowered and taken hostage in a headlock hold. Tour manager Chris Paluska was also injured. Responding within three minutes to a dispatch call made at 10:15pm, seven police officers entered through the front entrance and moved toward the stage. Officer James Niggemeyer came in through the back door, behind the stage. Gale only saw the officers in front of the stage; he did not see Niggemeyer, who was armed with a 12 gauge Remington 870 shotgun. Niggemeyer approached Gale from the opposite side of the stage past a group of security guards, and saw Gale lift his gun to Brooks' head, and fired a single shot as Gale noticed him. Gale was struck in the face with eight of the nine buckshot pellets and was killed instantly. Gale was found to have had 35 rounds of ammunition remaining. Two fans, including Mindy Reece, a certified nurse, administered CPR on Abbott until paramedics arrived, but were unable to revive him and he was pronounced dead at the scene. Early speculation about motive suggested that Gale, who was a Pantera fan, might have turned to violence in response to the breakup of the band, or the public dispute between Abbott and Pantera singer Phil Anselmo, but these were later ruled out by investigators. In VH1's documentary, Behind the Music, Damageplan's sound engineer Aaron Barnes stated that the whole time, after shooting Dimebag, Gale was looking for Vinnie, possibly planning to murder him too. Another conjecture was that Gale believed Abbott had stolen a song that he had written. About six months prior to the shooting, Gale got into an altercation at a Damageplan concert in Cincinnati where he damaged $5,000 worth of equipment while being removed from the stage by security.

Using a quote from the above article, answer the following question: Who shot him?
HHHHHH
Answer:
Moments into Damageplan's set, 25-year-old former Marine Nathan Gale shot Abbott five times in the head