Question: Mike Gibbons was an American boxer who claimed the Middleweight Champion of the World status following what Polish American professional boxer's murder?

full_context: Document 1: Esteban Gallard: Esteban Gallard (January 1, 1901 – October 7, 1929) was a Cuban boxer who found international fame under the nickname Kid Charol. While Charol never won a world boxing title, he did obtain popularity, especially in Argentina where he lived for the last years of his life after moving there from his Cuban hometown of Sagua la Grande. He had a relatively short boxing career before dying at age 28, holding only 45 bouts in an era when many boxers logged more than 100 career fights.
Document 2: Freddie Steele: Freddie Steele (December 18, 1912 – August 22, 1984) was a boxer and film actor born Frederick Earle Burgett in Seattle, Washington. He was recognized as the National Boxing Association (NBA) Middleweight Champion of the World between 1936 and 1938. Steele was nicknamed "The Tacoma Assassin" and was trained by Jack Connor, Johnny Babnick, and Ray Arcel, while in New York. His managers included George McAllister, Dave Miller, Eddie Miller, and Pete Reilly. He appeared as an actor in a number of Hollywood films in the 1940s, including Preston Sturges's "Hail the Conquering Hero".
Document 3: Robert Garcia (American boxer): Roberto Garcia Cortez (born January 29, 1975), best known as Robert Garcia, is an American former professional boxer who competed from 1992 to 2001, and held the IBF junior lightweight title from 1998 to 1999. He has since worked as a boxing trainer, and was voted Trainer of the Year by "The Ring" magazine in 2011, and by the Boxing Writers Association of America in 2012. Garcia is the older brother of professional boxer Mikey Garcia, who himself is a former junior lightweight world champion.
Document 4: Country McCleester: George "Country McCloskey" McCheester or John McCleester (fl. 1841-1850) was an American bare-knuckle boxer and sportsman involved in the early history of pugilism and prize fighting in Old New York. A well known fighter in his youth, his 1841 bout with Tom Hyer at Caldwell's Landing reportedly lasted nearly 3 hours and went to 101 rounds before the "Pride of Chatham Square" seconds threw up the sponge. Considered one of the greatest fights in the city's history, Hyer was recognized as the top fighter in the United States and awarded the American heavyweight championship. He and Yankee Sullivan were part of a group of promoters arrested following the death of boxer Thomas McCoy who died during a match against Christopher Lilly in Westchester County on September 13, 1842. Sullivan, who was the main promoter, was sentenced to two years in prison while McCleester and the others received light jail sentences or fines. McCleester had served as one of the cornermen during the bout.
Document 5: Dariusz Michalczewski: Dariusz Michalczewski (born 5 May 1968) is a Polish-German former professional boxer who competed from 1991 to 2005. He is a two-weight world champion, having held multiple world titles at light-heavyweight, including the WBO title from 1994 to 2003; the unified WBA, IBF, and lineal titles in 1997; and the WBO junior-heavyweight title from 1994 to 1995.
Document 6: Mike McNulty (boxing manager): Mike McNulty (1887 - 1965) was an old time, old style and old method boxing manager and trainer, who managed and trained several world champion boxers during the first half of the 20th century, including Mike O'Dowd, Johnny Ertel, Mike Gibbons and, also, trained Mike’s brother Tommy Gibbons, the Ring Boxing and International Boxing Hall of Fame. In 1965, Mike McNulty died at Studio City Convalescent Hospital in Studio City, California at the age of 78.
Document 7: Ted &quot;Kid&quot; Lewis: Ted "Kid" Lewis (born Gershon Mendeloff; 28 October 1893 – 1970) was an English professional boxer who twice won the World Welterweight Championship (147 lb). Lewis is often grouped alongside the all-time greats, with ESPN ranking him 41st on their list of the 50 Greatest Boxers of All-Time and boxing historian Bert Sugar placing him 46th in his Top 100 Fighters catalogue. Statistical boxing website BoxRec ranks Lewis as the 17th best welterweight of all-time and the 7th best UK boxer ever. He is a member of the International Jewish Sports Hall of Fame, the Ring Magazine Hall of Fame, and the International Boxing Hall of Fame
Document 8: Jeff Smith (boxer): Jerome "Jeff Smith" Jefferds (April 23, 1891 – February 3, 1962) was an American professional boxer who held the Australian version of the World Middleweight Title during his career. Despite his relative anonymity, Smith faced off against some the best fighters of his era, including Harry Greb, Gene Tunney, Mike Gibbons, Georges Carpentier, Les Darcy and Tommy Loughran. Statistical boxing website BoxRec lists Smith as the 17th greatest middleweight ever, while Ring Magazine founder Nat Fleischer ranked Smith as the #10 Middleweight of all-time. He was inducted into the Ring Magazine Hall of Fame in 1969 and the International Boxing Hall of Fame in 2013.
Document 9: Mike O'Dowd: Michael Joseph O'Dowd (April 5, 1895 in St. Paul, Minnesota – July 28, 1957) was an American boxer who held the World Middleweight Championship from 1917 to 1920. He won the title on November 14, 1917 by knocking out Al McCoy in the sixth round after dropping him six times. O'Dowd was the only active boxing champion to fight at the front during World War I (1918, while serving in the U.S. Army). During his career he claimed victories over Hall of Famers Jack Britton, Mike Gibbons, Kid Lewis and Jeff Smith. On February 25, 1918, he held the legendary Harry Greb to a draw. O'Dowd was knocked out just once in his career, his last fight on March 16, 1923. He was inducted into the Minnesota Boxing Hall of Fame in 2011 and the International Boxing Hall of Fame in 2014.
Document 10: Mike Gibbons: Mike Gibbons (July 20, 1887 in St. Paul, Minnesota – August 31, 1956) was an American boxer from 1908 to 1922. The brother of heavyweight Tommy Gibbons, Mike claimed Middleweight Champion of the World status in 1909 following Stanley Ketchel's murder. Although he never won the title, Gibbons is regarded as one of the all-time best welter and middleweight boxers by historians. Statistical boxing website BoxRec lists Gibbons as the #18 ranked middleweight of all time, while "The Ring Magazine" founder Nat Fleischer placed him at #9. The International Boxing Research Organization rates Gibbons as the 17th best middleweight ever and boxing historian Bert Sugar placed him 92nd in his Top 100 Fighters catalogue. Gibbons retired due to deteriorating vision. Following his boxing career he entered business in his native St. Paul, and became a member of the Minnesota Athletic Commission. Gibbons was elected to the Ring Magazine Hall of Fame in 1958, the International Boxing Hall of Fame in 1992, the World Boxing Hall of Fame in 1997, and the Minnesota Boxing Hall of Fame in 2010.
Document 11: Shorty Hogue: Willis 'Shorty' Hogue was a boxer in California during the 1940s, along with Lloyd Marshall, Charley Burley, Jack Chase (Young Joe Louis), Archie Moore and Eddie Booker. He had a twin brother, Willard, known as "Big Boy" Hogue, who also boxed in this era. No complete record exists for either brother, but Shorty Hogue was once ranked #3 at middleweight by Ring magazine. He scored three wins over Archie Moore and beat Jack Chase, Johnny "Bandit" Romero and Eddie Booker. His win over Booker earned him the California Middleweight Championship. Around this time, the World Championships were frozen by World War II, and most of the best middleweights of the era fought over the California title. Charley Burley stopped Hogue in 1942, and after that, Hogue's career hit the doldrums. Most of Hogue's bouts after this were knockout losses, including one to Eddie Booker, in which he lost the California Middleweight Championship. There is no record of his career outside of the years 1939 to 1942, but in those three years, he went 55-1. His only loss was to his cousin, Kole, whose record was an amazing 89-0.
Document 12: Leon Czolgosz: Leon Frank Czolgosz (Polish: "Czołgosz" ; May 5, 1873 – October 29, 1901) was an American anarchist and former steel worker who assassinated U.S. President William McKinley in September 1901. Czolgosz was executed just over seven weeks later.
Document 13: Stanley Ketchel: Stanisław Kiecal (September 14, 1886 – October 15, 1910), better known in the boxing world as Stanley Ketchel, was a Polish American professional boxer who became one of the greatest World Middleweight Champions in history. He was nicknamed "The Michigan Assassin." He was murdered at a ranch in Conway, Missouri, at the age of 24.
Document 14: Harry Greb: Edward Henry Greb (June 6, 1894 – October 22, 1926) was an American professional boxer. Nicknamed "The Pittsburgh Windmill", he was the American light heavyweight champion from 1922 to 1923 and world middleweight champion from 1923 to 1926. He fought a recorded 298 times in his 13 year-career, which began at around 140 pounds. He fought against the best opposition the talent-rich 1910s and 20s could provide him, frequently squaring off against light heavyweights and even heavyweights. Widely considered one of the best fighters of all time, Greb was named the 7th greatest fighter of the past 80 years by the "Ring Magazine", the 5th greatest fighter of all-time by historian Bert Sugar and ranked as the #1 middleweight and the #2 pound-for-pound fighter of all-time by the International Boxing Research Organization. Statistical boxing website BoxRec lists Greb as the #3 ranked middleweight of all-time and the 8th greatest pound-for-pound fighter ever.
Document 15: Jess Willard: Jess Myron Willard (December 29, 1881 – December 15, 1968) was a world heavyweight boxing champion known as the Pottawatomie Giant who knocked out Jack Johnson in April 1915 for the heavyweight title. He was known for his great strength and ability to absorb tremendous punishment, although today he is also known for his title loss to Jack Dempsey.
ground_truth: Stanley Ketchel