Question: How many people was this American contract killer and serial killer, who was the subject of the movie The Iceman, convicted of killing?

Context paragraphs:
Computer bridge: Computer bridge is the playing of the game contract bridge using computer software.  After years of limited progress, since around the end of the 20th century the field of computer bridge has made major advances.  In 1996 the American Contract Bridge League (ACBL) established an official World Computer-Bridge Championship, to be held annually along with a major bridge event.  The first championship took place in 1997 at the North American Bridge Championships in Albuquerque.  Since 1999 the event has been conducted as a joint activity of the American Contract Bridge League and the World Bridge Federation.  Alvin Levy, ACBL Board member, initiated this championship and has coordinated the event annually since its inception.  The event history, articles and publications, analysis, and playing records can be found at the official website.

Robert Joseph Silveria Jr.: Robert Joseph Silveria Jr. also known as "The Boxcar Killer", is an American serial killer currently serving a double life sentence in Wyoming.  He is on contract for an outside state.  Currently he is in Wyoming Medium Correction Institute.  He is the head cook as well as support system for numerous inmates.  Mr. Silveria was also convicted in Kansas for the killing of Charles Randall Boyd, and in Florida for the killing of Willie Clark.

List of serial killers by number of victims: A serial killer is a person who murders three or more people, in two or more separate events over a period of time, for primarily psychological reasons.  There are gaps of time between the killings, which may range from a few hours to many years.  This list shows serial killers from the 20th century to present day by number of victims.  In many cases, the exact number of victims assigned to a serial killer is not known, and even if that person is convicted of a few, there can be the possibility that he/she killed many more.

Richard Kuklinski: Richard Leonard Kuklinski (April 11, 1935 – March 5, 2006) was an American contract killer and serial killer who was convicted of murdering five people, though he likely killed at least several dozen more.  He was associated with members of the American Mafia, namely the DeCavalcante crime family of Newark, New Jersey, and the Five Families of New York City.

Charles Cullen: Charles Edmund Cullen (born February 22, 1960) is a former nurse who is the most prolific serial killer in New Jersey history and is suspected to be the most prolific serial killer in American history.  He confessed to authorities that he killed up to 40 patients during the course of his 16-year nursing career.  But in subsequent interviews with police, psychiatric professionals, and journalists Charles Graeber and Steve Kroft, it became clear that he had killed many more, whom he could not specifically remember by name, though he could often remember details of their case.  Experts have estimated that Charles Cullen may ultimately be responsible for 400 deaths, which would make him the most prolific serial killer in American history.

Cold North Killers: Canadian Serial Murder: Cold North Killers: Canadian Serial Murder is a 2012 Canadian non-fiction book written by Lee Mellor and published by Dundurn Press.  It documents the lives of sixty Canadian serial killers, with the earliest being Edward H. Rulloff and the most recent being Russell Williams.  The book uses Katherine Ramsland's interpretation of what constitutes a serial killer—someone who has killed at least two people on two separate occasions, and who attempted to or likely would have killed again—as outlined in her 2007 book "The Human Predator".  "Cold North Killer's" own definition of what constitutes a Canadian serial killer includes both Canadians who committed murder abroad (such as Keith Hunter Jesperson and Gordon Stewart Northcott) and non-Canadians who committed murder in Canada (like William Dean Christenson and Earle Nelson).

Randall Woodfield: Randall Brent "Randy" Woodfield (born December 26, 1950) is an American serial killer who was dubbed The I-5 Killer or The I-5 Bandit by the media due to the crimes he committed along the Interstate 5 corridor running through Washington, Oregon, and California.  Before his capture, the I-5 Killer was suspected of multiple sexual assaults and murders.  A native of Oregon, Woodfield was convicted of three murders and is suspected of killing up to 44 people.  He is currently incarcerated at the Oregon State Penitentiary.  In 2011, Woodfield was the subject of a Lifetime television movie "Hunt for the I-5 Killer".  The movie was based on the book "The I-5 Killer" by crime author Ann Rule.

The Iceman (film): The Iceman is an American biography crime thriller film based on the true story of longtime notorious hitman Richard Kuklinski.  Released in 2012 at the Venice Film Festival, the film was directed by Ariel Vromen, and stars Michael Shannon as Kuklinski, Winona Ryder, Chris Evans, and Ray Liotta.

Dexter (episode): "Dexter", or "Pilot", is the pilot episode of the first season television drama series "Dexter", which premiered on October 1, 2006 on Showtime in the United States.  The episode was written by developer James Manos, Jr. and directed by Michael Cuesta.  It was based on the opening of the novel "Darkly Dreaming Dexter" by Jeff Lindsay.  The pilot introduces the series' protagonist, Dexter Morgan (Michael C. Hall), a Miami Metro Police Department blood spatter analyst with a double life as a serial killer.  While solving murders in the Homicide division, Dexter also spends his time hunting and killing murderers and criminals who have escaped the justice system.  The pilot introduces the "Ice Truck Killer", a serial killer who targets prostitutes and leaves their bodies dismembered and bloodless, and the rivalry that develops between the killer and Dexter.

My Brother the Serial Killer: My Brother the Serial Killer is a 2012 American television documentary about serial killer Glen Rogers, otherwise known as the "Casanova Killer", who was convicted for a series of murders and arsons.  The documentary was narrated by Rogers' brother Clay Rogers and aired on Investigation Discovery in November 2012.  "My Brother the Serial Killer" received widespread media attention for Clay's claims that his brother was responsible for the 1994 murders of Nicole Brown Simpson and Ronald Lyle Goldman.

Supporting paragraphs: The Iceman (film) Richard Kuklinski
Answer: five