Question: Jon Roberts, who helped author American Desperado, was associated with which cartel?

Context paragraphs:
Jon Roberts: Jon Pernell Roberts (June 21, 1948 – December 28, 2011), born John Riccobono, was a noted drug trafficker and government informant, operated in the Miami area and was an associate of Colombia's Medellín Cartel during the growth phase in cocaine trafficking, 1975–1985.  After his arrest, he was able to avoid a lengthy prison sentence by becoming a cooperating witness and proactive informant for the federal government.  He was the author with Evan Wright of "American Desperado".

Charles Jennens: Charles Jennens (1700 – 20 November 1773) was an English landowner and patron of the arts.  As a friend of Handel, he helped author the libretti of several of his oratorios, most notably "Messiah".

Ioan Bianu: Ioan Bianu (1856 or 1857 – February 13, 1935) was an Imperial Austrian-born Romanian philologist and bibliographer.  The son of a peasant family from Transylvania, he completed high school in Blaj, where he became a disciple of Timotei Cipariu and Ioan Micu Moldovan.  As a youth, he espoused Romanian nationalism, and came into conflict with the Austro-Hungarian authorities, before finally emigrating to the Romanian Old Kingdom in 1876.  There, he attended the University of Bucharest, later joining the faculty, where he taught Romanian literary history.  He was affiliated with the Romanian Academy Library for over half a century, transforming the institution from the meager state in which he found it, and overseeing a five-fold increase of its collection.  He helped author two important multi-volume works detailing early books and manuscripts from his country, and was a founder of library and information science in his adoptive country.  Near the end of his life, struggling with deafness, Bianu withdrew from the Library in favor of his friend Radu R. Rosetti, but went on to serve as president of the Romanian Academy.

Asa Martin: Asa F. Martin (June 25, 1900 – August 15, 1979) was an American old time musician, singer and guitarist who made many recordings during the 1920s and 1930s and was closely associated with renowned fiddle player Doc Roberts, for whom he played rhythm guitar.  In turn, Roberts frequently played mandolin on Martin's recordings; Roberts' son James also sang duets with Martin under the name "Doc Roberts Trio".

Shaded Red: Shaded Red was a Christian alternative rock band from Denver, Colorado, in the United States.  It was formed in 1993 by brothers Jamie Roberts (vocals and guitar) and Jonathan Roberts (guitars, bass, trumpet, piano).  In 1997 they released their debut self-titled album through Cadence.  On January 17, 1998, the band was struck by tragedy when their van hit a patch of black ice returning from a concert.  Drummer Chris Yeoman was killed and Jon Roberts was left with a shattered pelvis.  It was at this time the band considered calling it quits but decided to press on instead.

Railroad Bill: Morris Slater, a former circus hand and turpentine worker, lived life on the edge, becoming legendary as Railroad Bill, the most celebrated African American desperado in history.

Vanessa Raw: Vanessa Raw (born 28 September 1984 in Hexham) is an English professional triathlete, member of the British Olympic Triathlon Academy Squad and a recognized artist.  She currently lives in London and Coached by Tom Bennett from T2Coaching and is supported by Jon Roberts (S&C) and St Marys University College (Physiology).  She is currently ranked 34th in the World Triathlon Series after season high 15th place at Kitzbuhel and 18th-place finishes at Stockholm.  She will be representing GBR at the London Grand Final in September 2013.

American Desperado: American Desperado is a 2011 book written by journalist Evan Wright and Jon Roberts, a subject of the 2006 documentary "Cocaine Cowboys".

It's a Shame About Ray: It's a Shame About Ray is the fifth album by American alternative rock band The Lemonheads.  It was released on June 2, 1992.  Tom Morgan of Australian band Smudge helped author the album, The Robb Brothers produced, and Juliana Hatfield played bass and sang backing vocals on some songs.

Bill Blunden (author): Bill Blunden (born 1969) is the author of several books including "," "Behold A Pale Farce: Cyberwar, Threat Inflation & The Malware Industrial Complex", "Cube Farm", and "Software Exorcism".  The jacket of the former work lists his credentials MCSE, MCITP, and Enterprise Administrator.  He is also active in the social sciences space and helped author articles appearing in "".

Supporting paragraphs: American Desperado Jon Roberts
Answer: Colombia's Medellín Cartel