Question: Who was Leigh Whannell's friend who directed Saw?

Context paragraphs:
Saw III: Saw III is a 2006 American horror film directed by Darren Lynn Bousman from a screenplay by Leigh Whannell and story by James Wan and Whannell.  It is the third installment in the "Saw" franchise and stars Tobin Bell, Shawnee Smith, Angus Macfadyen, Bahar Soomekh, and Dina Meyer.  "Saw III" marks the first appearances of Costas Mandylor and Betsy Russell, albeit minor roles; they would later become major characters in the series.

Saw (franchise): Saw is an American horror franchise distributed by Lionsgate, produced by Twisted Pictures and created by James Wan and Leigh Whannell, that consists of eight feature films and additional media.  In 2003, Wan and Whannell made a short film to help pitch as a potential feature film.  This was successfully done in 2004 with the release of the first installment at the Sundance Film Festival.  It was released theatrically that October.  The sequels were directed by Darren Lynn Bousman, David Hackl, and Kevin Greutert, and were written by Wan, Whannell, Bousman, Patrick Melton, and Marcus Dunstan, and were released subsequently every October, on the Friday before Halloween, between 2004 and 2010.  Both of the creators remained with the franchise as executive producers.  On July 22, 2010, producer Mark Burg confirmed that the seventh film, "Saw 3D", is the final installment of the series.  Lionsgate reportedly expressed interest in continuing the franchise in 2012 with a reboot.  However, in November 2013, it was reported that they were in active development of a sequel.

Saw (2004 film): Saw is a 2004 American horror film directed by James Wan.  It is Wan's feature film directorial debut.  The screenplay, written by Leigh Whannell, is based on a story by Wan and Whannell.  The film stars Cary Elwes, Danny Glover, Monica Potter, Michael Emerson, Ken Leung, Tobin Bell and Leigh Whannell.  In the film, Elwes and Whannell portray two men who awake to find themselves chained in a large dilapidated bathroom, with one being ordered to kill the other or his family will die.  It is the first installment in the "Saw" franchise.

List of Saw media: "Saw" is a horror film series created by James Wan and Leigh Whannell and distributed by Lions Gate Entertainment and Twisted Pictures.  The films take place in a fictional universe that revolves around a serial killer, dubbed The Jigsaw Killer, who captures victims who he believes do not appreciate their life and puts them into traps to test their survival instinct.  While starting as a film series, "Saw" has evolved to encompass numerous media forms including video games and comics as well as mazes and a roller coaster.  According to "The New York Times" in October 2009, including international sales and revenue from DVDs, television and merchandise, the "Saw" series has taken in more than $1 billion, making it one of the highest-grossing horror franchises in history.  This comprises over 28 million DVDs sold and $665 million worth of ticket sales for the first five films alone, along with various other merchandise.  On July 23, 2010, the franchise was recognized by the Guinness World Records as the "Most Successful Horror Movie Series".

Insidious: The Last Key: Insidious: The Last Key is an upcoming American supernatural horror film directed by Adam Robitel and written by Leigh Whannell.  It is the fourth installment in the "Insidious franchise", and the second chronologically following 2015's "".  The film stars Lin Shaye, Leigh Whannell, Angus Sampson, Spencer Locke, Kirk Acevedo and Bruce Davison.

Leigh Whannell: Leigh Whannell (born 17 January 1977) is an Australian screenwriter, producer, director and actor.  He is best known for writing films directed by his friend James Wan, including "Saw" (2004), "Dead Silence" (2007), "Insidious" (2011) and "" (2013).  Whannell made his directorial debut on "", which was released in 2015.

List of Saw characters: The "Saw" series of horror films features a large cast of characters created primarily by directors and screenwriters James Wan, Leigh Whannell, Darren Lynn Bousman, Patrick Melton, and Marcus Dunstan.  The series focuses on the character of John Kramer (Tobin Bell), the "Jigsaw Killer", who seeks out those he considers to be wasting their lives and subjects them to torturous and lethal traps, referred to as "tests" and "games", in an attempt to make them appreciate living.  The series comprises eight films: "Saw" (2004), "Saw II" (2005), "Saw III" (2006), "Saw IV" (2007), "Saw V" (2008), "Saw VI" (2009), "Saw 3D" (2010) and "Jigsaw" (2017).

Insidious: Chapter 3: Insidious: Chapter 3 is a 2015 American-Canadian supernatural horror film written and directed by Leigh Whannell in his directorial debut.  It is a prequel to the first two films and the third installment in the "Insidious" franchise.  The film stars Dermot Mulroney and Stefanie Scott, with Angus Sampson, Whannell and Lin Shaye reprising their roles from the previous films.  The film was released on June 5, 2015, and grossed $113 million against a budget of $10–11.2 million.

Saw II: Saw II is a 2005 American horror film, a sequel to 2004's "Saw" and the second installment in the "Saw" franchise, directed and co-written by Darren Lynn Bousman and series creator Leigh Whannell.  The film stars Donnie Wahlberg, Franky G, Glenn Plummer, Beverley Mitchell, Dina Meyer, Emmanuelle Vaugier, Erik Knudsen, Shawnee Smith, and Tobin Bell.

Saw (2003 film): Saw (retrospectively also known as Saw 0.5) is an Australian short subject horror film, released in 2003.  It was directed by James Wan and written by Wan and Leigh Whannell, the latter also starring in it.  It was originally used to pitch their script for a full-length feature film of the same name to various studios and actors.  The full-length film was eventually made in 2004.  The short film later became a scene in "Saw", with Shawnee Smith as Amanda Young wearing the Reverse Bear Trap device instead of David.  The original short can be viewed on the second disc of "Saw: Uncut Edition".

Supporting paragraphs: Saw (2004 film) Leigh Whannell
Answer: James Wan