Question: Which Hells Angel member stabbed and beat an attendant of the 1969 counterculture-era rock concert in the United States?

Passages:
The Brottby Concert (Swedish: "Brottbykonserten" ) was a Neo-Nazi rock concert held at the Yesterday dancing venue in Brottby, Sweden, the evening of January 3, 1998.  Participating bands and audience members came from several countries.  Riot police stormed the concert, arresting about 250 people, several suspected for hate speech.  Foreign participants—for example, from the United States—stated during the trial they were unaware the nazi salute was considered hate speech in Sweden.  The concert and subsequent trials was widely publicised by the domestic press. The Altamont Speedway Free Festival was a counterculture-era rock concert in 1969 in the United States, held at the Altamont Speedway in northern California on Saturday, December 6. John F. Kennedy High School is a public school located in Mt. Angel, Oregon, United States, as part of the Mt. Angel School District.  The school was originally Mt. Angel Preparatory School run by the Benedictine monks of Mount Angel Abbey, and was founded in 1887.  The Benedicitnes ran the school until 1964, when they turned its administration over to St. Mary's Catholic Church, located in Mt. Angel.  The parish ran the school for five years until closing it in 1969.  It was reopened one year later as John F. Kennedy High School, and remains so today. Wenzell Baird Bryant (Columbus, Indiana, December 12, 1927 – Hemet, California, November 13, 2008) was an American filmmaker.  He is best known as the cameraman on the Albert Maysles film "Gimme Shelter" who filmed the fatal stabbing of Rolling Stones concertgoer Meredith Hunter by Hells Angel Alan Passaro at the Altamont Free Concert in December 1969. Live'r Than You'll Ever Be is a bootleg recording of the Rolling Stones' concert in Oakland, California, from 9 November 1969.  It was one of the first live rock music bootlegs and was made notorious as a document of their 1969 tour of the United States.  The popularity of the bootleg forced the Stones' label Decca Records to release the live album "Get Yer Ya-Yas Out!  The Rolling Stones in Concert" in 1970.  "Live'r" is also one of the earliest commercial bootleg recordings in rock history, released in December 1969, just two months after the Beatles' "Kum Back" and five months after Bob Dylan's "Great White Wonder".  Like the two earlier records, "Live'r"'s outer sleeve is plain white, with its name stamped on in black ink. Barry Fey (1938 – April 28, 2013) was an American rock concert promoter from Colorado who was best known for bringing prominent music acts to the United States for the first time. Hyde Park in London, England, has been an important venue for rock music concerts since the late 1960s.  The music management company Blackhill Enterprises held the first rock concert there on 29 June 1968, attended by 15,000 people.  On the bill were Pink Floyd, Roy Harper and Jethro Tull.  The supergroup Blind Faith (featuring Eric Clapton and Steve Winwood) played their debut gig in Hyde Park on 7 June 1969.  The Rolling Stones headlined a concert (later released as The Stones in the Park) on 5 July that year, two days after the death of founding member Brian Jones, and is now remembered as one of the most famous gigs of the 1960s.  The early gigs from 1968–71 were free events, while later concerts were pay-to-enter. Meredith Curly Hunter, Jr. (October 24, 1951 – December 6, 1969) was an 18-year-old African-American man who was killed at the 1969 Altamont Free Concert.  During the performance by The Rolling Stones, Hunter approached the stage, and was violently driven off by members of the Hells Angels motorcycle club who had been contracted to serve as security guards.  He subsequently returned to the stage area, drew a revolver, and was stabbed and beaten to death by Hells Angel Alan Passaro. This is a list of BoA Concert Tours by Kwon Boa (Korean: 권보아, Chinese: 權珤雅, Japanese: クォン·ボア, born November 5, 1986), commonly stylized and known by her stage name BoA, which is an acronym for Beat of Angel.  She is a South Korean singer and actress active in South Korea, Japan, and the United States, who referred to as the Queen of Korean Pop. Sasha & John Digweed present Delta Heavy is a DVD release from System Recordings which chronicles Sasha & John Digweed's "Delta Heavy" tour of the United States.  It was released in 2005, three years after the original tour.  "Delta Heavy" is known for being one of the first DJ tours to incorporate a rock concert atmosphere into traditional DJ venues.  The DVD package includes guest commentary from Jimmy Van M and Nick Warren.

Supporting sentences:
 He subsequently returned to the stage area, drew a revolver, and was stabbed and beaten to death by Hells Angel Alan Passaro. The Altamont Speedway Free Festival was a counterculture-era rock concert in 1969 in the United States, held at the Altamont Speedway in northern California on Saturday, December 6.