Question: Joe Lefors was responsible for the 1903 arrest of Thomas Horn for the murder of what man's son?

Context paragraphs:
William Brydges: William Brydges was a Canadian man whose arrest for murder resulted in the leading Supreme Court of Canada case "R v Brydges" on the right of a detainee to access duty counsel.  His case was a Canadian precedent, and created significant controversy after the Supreme Court of Canada upheld his acquittal.  He was found to have been denied access to an attorney because he was not informed of legal services available to him when he told police he could not afford a lawyer.  This case had nationwide ramifications, requiring all police officers to advise a person under arrest of the availability of legal services even if they couldn't afford them.

Thomas Horn (disambiguation): Thomas Horn is an American actor.

Space Warriors (2013 film): Space Warriors is a 2013 American film, directed by Sean McNamara, starring Thomas Horn, Josh Lucas, and Danny Glover.  The film was released in USA on 26 April 2013.

Extremely Loud &amp; Incredibly Close (film): Extremely Loud & Incredibly Close is a 2011 American drama film adaptation of the novel of the same name by Jonathan Safran Foer, directed by Stephen Daldry and written by Eric Roth.  It stars Thomas Horn, Tom Hanks, Sandra Bullock, Max von Sydow, Viola Davis, John Goodman, Jeffrey Wright, and Zoe Caldwell.  Production took place in New York City.  The film had a limited release in the United States on December 25, 2011 by Warner Bros.  Pictures, and a wide release on January 20, 2012.  Despite mixed reviews, the film was nominated for two Academy Awards, Best Picture and Best Supporting Actor for von Sydow.  The film earned $55.2 million.  The film was released in Blu-ray, DVD, and digital download formats in Region 1 on March 27, 2012.

Judy Buenoano: Judias "Judy" Buenoano (born Judias Welty, also known as Judias Goodyear and Judias Morris) (April 4, 1943 – March 30, 1998) was a convicted murderer who was executed for the 1971 murder of her husband James Goodyear.  She was also convicted for the 1980 murder of her son Michael Buenoano and of the 1983 attempted murder of her fiancé John Gentry.  She is also acknowledged to have been responsible for the 1978 death of her boyfriend Bobby Joe Morris in Colorado; however, by the time authorities made the connection between Buenoano and Morris, she had already been sentenced to death in the state of Florida.

Thomas Horn: Thomas Horn (born December 14, 1997) is an American actor best known for his role in the drama film "Extremely Loud and Incredibly Close" (2011).

Malcolm Naden: Malcolm Johnn Naden (born 5 November 1973) is an Australian former fugitive from the law.  At the time of his capture and arrest in March 2012, Naden was reported as being one of Australia's most wanted men and his arrest attracted international media coverage.  Naden was in hiding from June 2005 until March 2012, wanted over murder and indecent assault offences.  He was the most wanted man in the Australian state of New South Wales.

Tom Horn: Thomas Horn, Jr. (November 21, 1860 – November 20, 1903) was an American Old West scout, who carried out varied roles as hired gunman, Pinkerton, range detective, cowboy, and soldier.  Believed to have committed 17 killings as a hired gunman in the West, in 1902 Horn was convicted of the murder of 14-year-old Willie Nickell near Iron Mountain, Wyoming.  Willie was the son of sheep rancher Kels Nickell, who had been involved in a range feud with neighbor and cattle rancher Jim Miller.  On the day before his 43rd birthday, Horn was executed by hanging in Cheyenne, Wyoming.

Adrian P. Thomas: Adrian P. Thomas was a father of seven children living in Troy, New York, when, in September 2008, his four-month-old son died.  A preliminary medical examination indicated that the infant died from head trauma.  The police interrogated Thomas for nearly 10 hours during which he confessed to throwing his son on the bed three times.  The entire interrogation was videotaped.  He was charged with second-degree murder, found guilty, and sentenced to 25 years to life in prison.  In 2011, Grover Babcock and Blue Hadaegh were looking for an example of a coerced confession as the basis for a documentary film they were planning and they used Thomas' interrogation video to make the documentary "Scenes of a Crime".  Thomas appealed his conviction based on a coercive interrogation, however, the state appellate justices of New York denied his appeal in 2012.  Thomas then appealed his conviction to the New York Court of Appeals.  In February 2014, the seven judges unanimously ruled that Thomas must have another trial excluding the videotaped confession.  A second trial was held and on June 12, 2014, the jury found him not guilty of second degree murder of his infant son.  The case created controversy about how much coercion is legally permissible in police interrogations.

Joe Lefors: Joe Lefors (February 20, 1865 – October 1, 1940) was a lawman in the closing years of the Old West.  He is best known for the arrest of gunman Tom Horn in 1903 for the alleged murder of 14‑year-old sheepherder Willie Nickell, which has since come into question, and it has long been believed that Lefors falsified evidence helping to convict the wrong man for the murder.

Supporting paragraphs: Joe Lefors Tom Horn
Answer: Kels Nickell