Question: What German ace-of-aces was shot down by Cedric Bassett Popkin during World War 1?

Context articles: Manfred von Richthofen
Snowy Evans
Cedric Popkin
World War 1 in Colour
George G. Finch
Vauquois
James Zimmermann
Otto Hutter
Mike Shuster
Sinking of the RMS Lusitania

Manfred Albrecht Freiherr von Richthofen (2 May 1892 – 21 April 1918), also known as the "Red Baron", was a fighter pilot with the German Air Force during World War I.
 He is considered the ace-of-aces of the war, being officially credited with 80 air combat victories.
Willy John "Snowy" Evans (  1891 –1925) was a Lewis machine gunner in the Royal Australian Artillery (RAA) during World War I.
 Unsolved History, produced by Discovery Channel credited him with firing the shot that killed Manfred von Richthofen ("The Red Baron"), near Vaux-sur-Somme, France on 21 April 1918.
 However, most sources attribute the feat to Sergeant Cedric Popkin of the 24th Machine Gun Company.
 Other sources have suggested that Gunner Robert Buie, also of the 53rd Battery, fired the fatal shot, but there is now little support for this theory.
Cedric Bassett Popkin (Born 20 June 1890, died 26 January 1968) is considered the person most likely to have killed German ace Manfred von Richthofen — also known as the "Red Baron" — on 21 April 1918.
 Popkin was an anti-aircraft (AA) machine gunner with the First Australian Imperial Force (AIF), during World War I.
World War 1 in Colour is a documentary narrated by Kenneth Branagh.
 The first of its six parts aired on 23 July 2003 in the United Kingdom.
 It was released on DVD in the United States as "World War 1 in Color" on 10 May 2005.
 The documentary consists of colourised footage from World War I.
Maj. Gen. George G. Finch became the Senior Leader of the US Air National Guard; (Chief of the Air Division National Guard Bureau) (1948-1950) In June 1953 it was reported that Gen. Mark W. Clark would retire and be replaced by Maj. Gen George G. Finch on the UN command delegation to the Korean armistice talks George G. Finch, born April 11, 1902 in Dade City, Florida, is considered one of the pioneers in United States aviation history.
 He began his military career during World War 1, enlisting in the Aviation Section of the Army's Signal Corps in 1918.
 He remained in the Reserve Corps after the war, and in 1926, became Commander, 27th Pursuit Squadron, 1st Pursuit Group.
 In 1940, Georgia Governor Ed Rivers commissioned him to form the first flying unit of the Georgia Air National Guard.
 The unit was mobilized into the U.S. Army in September, 1941, with Major Finch as commander.
 After World War II, he was a leading critic of efforts to eliminate the air arm of the National Guard during peacetime.
 General Finch gained the respect and admiration of Air National Guardsmen throughout the nation with his steadfast support and successful efforts to preserve the Air Guard.
 He became the first Chief of the Air Force Division of the National Guard Bureau in 1948.
 Under his leadership, the Air National Guard built to combat readiness and was among the first components called into service after the outbreak of the Korean War.
 As a result of General Finch's vision and perseverance, 45,000 highly trained officers and airmen of 22 wings and 65 squadrons gave the Air Force the strength it needed in the early, critical phases of the Communist drive down the Korean peninsula.General Finch served as the senior Air Force member of the United Nations negotiating team at the peace talks at Panmunjom, Korea, and received the Legion of Merit for outstanding service in 1955; General Finch assumed command of Fourteenth Air Force, Robins AFB, Georgia, becoming the nation's first Air National Guardsman to head a numbered air force.
 General Finch had a career of "firsts" including the US Army's first night landing with a single, five-million-candlepower floodlight in 1927.
 He also established and endowed the General John P. McConnell Award at the United States Air Force Academy.
 Considered by many as the father of the strong, independent Air National Guard existing today, General Finch retired in 1957.
 No man has had greater impact on the Air Force Reserve and National Guard than has General George G. Finch.A graduate of the University of Georgia and a member of the Georgia Bar, General Finch was enshrined in the Georgia Aviation Hall of Fame May 18, 1996.
During World War 1, Vauquois was the site of violent mine warfare, also in connection with the Battle of Verdun (1916).
 From 1915 to 1918, French and German tunneling units fired 519 separate mines at Vauquois, and the German gallery network beneath the village hill (the "Butte de Vauquois") grew to a length of 17 km .
 Vauquois was completely destroyed and many huge craters and dugouts remain.
James Zimmermann (1886–1917) was a British tennis player in the years before World war 1.
 His father was German and James was embarrassed by his German name, so he abbreviated his surname to Mann.
 Zimmermann reached the quarter finals of the Wimbledon men's singles in 1912 (where he lost to Alfred Beamish).
 He lost in the second round at Wimbledon in 1913.
 According to his obituary in the Sydney newspaper "Referee" on 17 October 1917, Zimmermann was "always popular with the crowd, for his garrulity on court, though sometimes disconcerting to his opponents, he had a vein of humour and irresponsibility".
 In 1915 his habit of sleepwalking led him into danger, when he was found wandering on the Brighton railway line near Victoria station (he was sentenced to six months imprisonment, though the sentence was quashed on appeal).
 In World War 1, Zimmermann was a sergeant in the H. A. C. and died from wounds sustained in action in 1917.
Otto Fred Hutter (b 29 February 1924) is Emeritus Regius Professor of Physiology at the University of Glasgow, is a physiologist.
 He was born in Vienna, becoming a British citizen in 1947., His father was an estate agent and his mother had been a nurse in World War 1.
 He first attended secondary school at the Zwi Perez Chajes Gymnasium.
 He left Vienna in December 1938 as part of the Kindertransport which allowed Jewish children to escape the German occupation.
 After arriving in the UK, he attended the Bishop Stortford College as a boarder.
 From 1942, after leaving school, he worked as a laboratory technician at the Wellcome Physiological Research Laboratories in Beckenham, Kent.
 One project addressed the standardisation of penicillin production, then of considerable importance for the war effort.
Mike Shuster was a diplomatic correspondent and a roving foreign correspondent for National Public Radio in the United States.
 He is currently the executive producer of The Great War Project, a website examining the impact of World War 1 on our world, a century after it ended.
 On that website, (greatwarproject.org), he writes the blog "Catastrophe, A Blog of World War One."
The sinking of the Cunard ocean liner RMS "Lusitania" occurred on Friday, 7 May 1915 during the World War 1, as Germany waged submarine warfare against the United Kingdom which had implemented a naval blockade of Germany.
 The ship was identified and torpedoed by the German U-boat "U-20" and sank in 18 minutes.
 The vessel went down 11 mi off the Old Head of Kinsale, Ireland, killing 1,198 and leaving 761 survivors.
 The sinking turned public opinion in many countries against Germany, contributed to the American entry into World War I and became an iconic symbol in military recruiting campaigns of why the war was being fought.