Joseph Dominick "Joe" Pistone, alias Donnie Brasco, (born September 17, 1939), is a former FBI agent who worked undercover for six years infiltrating the Bonanno crime family and to a lesser extent the Colombo crime family, two of the Five Families of the Mafia in New York City.
 Pistone was an FBI agent for 27 years.
John Vaughn Blake (1888 – June 29, 1964) was a former American football player and FBI agent.
 He played football for Dan McGugin's Vanderbilt Commodores football teams with his brothers Dan and Bob.
 Dan, Bob, and Vaughn were captains of the 1906, 1907, and 1908 respectively.
 Vaughn was an end on the football team, selected All-Southern in 1908.
 He was later an FBI agent involved with the capture of Alvin Karpis.
Barry Crane, born Barry Cohen, (November 10, 1927 – July 5, 1985) was a prolific television producer and director, and a bridge player who "won more titles than anyone else in the history of the game".
 According to the American Contract Bridge League (ACBL), he was "widely recognized as the top matchpoint player of all time"—the tournament format commonly played in private clubs.
"Donnie Fatso" is the ninth episode in the twenty-second season of the American animated television series "The Simpsons".
 It first aired on the Fox network in the United States on December 12, 2010.
 The plot revolves around an FBI agent, who helps Homer go undercover to infiltrate Fat Tony's mob.
 Homer agrees to this in hopes of decreasing his sentence after being charged for bribery.
 This episode is a reference to "Goodfellas" as well as real-life FBI agent Donnie Brasco.
John C. "Jack" Ryan (born 19 June 1938) is a former FBI agent and police officer.
 He had been an FBI agent between 1966 and 1987 before being fired for refusing to investigate nonviolent activists.
 He lost his job in September 1987 ten months short of retirement.
 He was thus ineligible for a full pension and had to live in a homeless shelter.
 In a report by the "LA Times", he stated his belief that the Bureau could reinstate him to a position which would not conflict with his personal beliefs that U.S. involvement in Central America is "violent, illegal and immoral."
Lon Tomohisa Horiuchi (born June 9, 1954) is the American FBI agent who shot Vicki Weaver at Ruby Ridge in 1992.
 An FBI HRT sniper and former US Army officer, he was involved in controversial deployments during the 1992 Ruby Ridge standoff and 1993 Waco siege.
 In 1997, Horiuchi was charged with manslaughter for the death of Vicki Weaver at Ruby Ridge, but the charges were later dropped.
Rockmond Dunbar (born January 11, 1973 in Berkeley, California) is an American actor.
 He is best known for his roles as Baines on the NBC series "Earth 2", Kenny Chadway on Showtime's "Soul Food", and Benjamin Miles "C-Note" Franklin on the FOX crime drama "Prison Break".
 He also played Sheriff Eli Roosevelt on the FX Drama series "Sons of Anarchy", FBI Agent Dennis Abbott on "The Mentalist", and FBI Agent Abe Gaines in the Hulu series "The Path".
Barry Cohen (born c. 1938) is a criminal, personal injury, civil and qui tam attorney in Florida's Tampa Bay Area.
 Cohen was hired by the Council on American–Islamic Relations (CAIR) to represent the family of Ibragim Todashev, an unarmed Chechen shot to death while being questioned by the FBI in relation to the Boston Marathon bombing.
 He has been characterized as a fighter for his aggressive legal tactics.
Herman Edward "Ed" Hollis (January 1903 – November 27, 1934) was an American law enforcement official and Federal Bureau of Investigation (FBI) special agent.
 As an FBI special agent in the 1930s, Hollis worked with agents Melvin Purvis, Samuel P. Cowley and others fighting bank robbers, gangsters and organized crime in the Chicago area during the Great Depression.
 Hollis is best known for having been killed in the line of duty during an intense shootout with Chicago-area bank robber Lester Gillis, a.k.a. Baby Face Nelson, at the Battle of Barrington in 1934.
 Hollis was also one of the three FBI special agents who shot John Dillinger near the Biograph Theater earlier that year, resulting in Dillinger's death.
 One controversial account also implicates Hollis in the death of Pretty Boy Floyd.
 Hollis served as a special agent for the FBI's field offices in Kansas City, Cincinnati, and Chicago for over seven years; at the time of his death, he was 31 years old.
Ibragim Todashev ("Ибрагим Тодашев"; September 22, 1985 – May 22, 2013) was a Chechen American former mixed martial artist and friend of suspected Boston Marathon bomber and former amateur boxer, Tamerlan Tsarnaev.
 At his apartment in Orlando, Florida, he was shot dead by FBI agent Aaron McFarlane during a police interview on May 22, 2013.
 He had allegedly attacked the agent, with a pipe or stick, while writing a statement about the Boston Marathon bombings and a triple homicide that took place in Waltham, Massachusetts, on September 11, 2011.
 The investigators involved in the incident said that Todashev had implicated both himself and Tamerlan Tsarnaev in the Waltham murders before he was killed.

Question: Barry Cohen represent the family of a Chechen suspect that was shot to death by what FBI agent?
Answer: Aaron McFarlane