Question: When did the world champion freestyle wrestler murdered by John du Pont die?

Context articles: Mark Schultz (wrestler)
Dupont Circle Fountain
Dauren Kurugliev
Phi Kappa Sigma
Allaire du Pont
Abdusalam Gadisov
Foxcatcher
Du Pont Motors
John du Pont
Dave Schultz (wrestling)

Mark Philip Schultz (born October 26, 1960) is an American Olympic and 2-time World champion freestyle wrestler and a Distinguished Member of the National Wrestling Hall of Fame, the San Jose Sports Hall of Fame, the California Wrestling Hall of Fame, and the San Mateo Peninsula Sports Hall of Fame.
 Additionally, he was promoted to the rank of black belt in Brazilian Jiu-Jitsu by Master Pedro Sauer on January 23, 2016.
The Dupont Circle Fountain, formally known as the Rear Admiral Samuel Francis Dupont Memorial Fountain, is a fountain located in the center of Dupont Circle in Washington, D.C. It honors Rear Admiral Samuel Francis Du Pont, a prominent American naval officer and member of the Du Pont family.
 The fountain replaced a statue of Du Pont that was installed in 1884.
 Designed by Henry Bacon and sculpted by Daniel Chester French, the fountain was dedicated in 1921.
 Prominent guests at the dedication ceremony included First Lady Florence Harding, Secretary of War John W. Weeks and Secretary of the Navy Edwin Denby.
Dauren Khalidovich Kurugliev (Russian: Даурен Халидович Куруглиев ; 12 July 1992, Makhachkala) is a Lezgin heritage Dagestani-born Russian freestyle wrestler.
 2017 European champion.
 He is Russian Junior National Champion 2011, North Caucasian Federal District Freestyle wrestling tournament winner 2011, 2013.
 National Master of Sports in Freestyle Wrestling.
 Kurugliev competed in the World Cup 2015 in Los Angeles, California and he won all the wrestling matches, 3-0.
 He defeated 3-time NCAA All-American champion Penn State Nittany Lions Wrestling Ed Ruth of USA (by fall), he won Usukhbaatar Purevee of Mongolia and Aleksander Gostiev of Belarus.
 He trains with world champion Abdusalam Gadisov.
 After American World Cup, In Russian National Freestyle Wrestling Championships 2015 he lost in the second round and was eliminated from the сhampionships.
 On 5 July 2015 on the Ali Aliyev Memorial he lost in the gold medal match to Shamil Kudiyamagomedov of Russia.
Phi Kappa Sigma (ΦΚΣ) is an international all-male college secret and social fraternity.
 Its members are known as PKS, Phi Kaps, Skulls and sometimes Skullhouse, the latter two because of the skull and crossbones on the fraternity's badge and coat of arms.
 Phi Kappa Sigma was founded by Dr. Samuel Brown Wylie Mitchell at the University of Pennsylvania.
 Mitchell recorded the initial ideas and concepts of Phi Kappa Sigma on August 16, 1850.
 He then began to discuss the idea with other students, first Charles Hare Hutchinson, and then Alfred Victor du Pont (son of Alfred V. du Pont), John Thorne Stone, Andrew Adams Ripka, James Bayard Hodge, and Duane Williams.
 The seven men formally founded the fraternity on October 19, 1850 becoming the founding fathers of Phi Kappa Sigma Phi Kappa Sigma was a charter member of the North-American Interfraternity Conference, and is headquartered in Chester Springs, Pennsylvania.
Allaire du Pont (May 4, 1913 – January 6, 2006) was an American sportswoman and a member of the prominent French-American Du Pont family of chemical manufacturers who is most remembered as the owner of the Thoroughbred horse racing Hall of Fame champion, Kelso.
Abdusalam Mamatkhanovich Gadisov (born 26 March 1989 in Dagestan) is an Avar – Dagestani born-Russian freestyle wrestler.
 He competed in the freestyle 96 kg event at the 2012 Summer Olympics; after defeating Taimuraz Tigiyev in the qualifications, he was eliminated by Reza Yazdani in the 1/8 finals.
 In 2014 he became World freestyle wrestling champion in 97 kg, and runner-up in 2015.
 In 2012 he became Russian national champion in final the match he defeated Olympic Champion and five time World Champion Khadzhimurat Gatsalov.
 He won Russian National Freestyle Wrestling Championships 2015 again and also won in 2016.
 Gadisov took the silver medal in the 2015 World Freestyle Wrestlng Championships, losing in the finals to Kyle Snyder, who became the youngest World Wrestling Champion in US history.He is devout Sunni Muslim
Foxcatcher is a 2014 American true crime sports drama film produced and directed by Bennett Miller.
 Written by E. Max Frye and Dan Futterman, the film stars Steve Carell, Channing Tatum, and Mark Ruffalo.
 The film's plot is loosely based on the events surrounding multimillionaire Du Pont family heir and wrestling enthusiast John du Pont's 1986 recruitment of 1984 U.S. Olympic gold medalist brothers Mark (Freestyle Wrestling - 82 kg) and Dave Schultz (Freestyle Wrestling - 74 kg) to help coach U.S. wrestlers for participation in national, world, and Olympic competition, and the subsequent murder of Dave by John du Pont in January 1996.
 Although the film's action is largely set at Foxcatcher Farm, du Pont's now-broken-up 800-acre suburban Philadelphia estate, the majority of the movie was filmed in the Pittsburgh metropolitan area.
Du Pont Motors was founded by E. Paul du Pont to produce marine engines for the Allied nations in World War I.
 After the war, the Du Pont Motor Company produced extremely high-end automobiles.
 The cars were manufactured in Wilmington, Delaware.
John Eleuthère du Pont (November 22, 1938 – December 9, 2010) was an American philanthropist and heir to the Du Pont family fortune, he had been a published ornithologist, philatelist, philanthropist, conchologist, sports enthusiast, self-styled wrestling coach.
 He died in prison while serving a sentence of 30 years in prison for the murder of Dave Schultz.
David Leslie "Dave" Schultz (June 6, 1959 – January 26, 1996) was an American Olympic and world champion freestyle wrestler, a seven-time World and Olympic medalist.
 He coached individuals and teams at the college level and also privately.
 He was shot and killed by John Eleuthère du Pont, a millionaire philanthropist who sponsored the private Foxcatcher wrestling team at an amateur sports center, known as Foxcatcher Farm, he set up on his estate in Pennsylvania.