Question: Who wrote the screen play for the film that had a soundtrack release called Saw?

Context paragraphs:
Up the Creek (song): "Up the Creek" is a non-album single by American rock band Cheap Trick, released as the title track for the 1984 film "Up the Creek", appearing on the film's soundtrack release as the first/opening track.  The song was written by Rick Nielsen and musician/songwriter Randy Bishop.  Bishop also wrote/co-wrote a lot of the soundtrack's material, including "Chasin' The Sky" by The Beach Boys, "The Heat" by Heart and "One Track Heart (Passion In The Dark)" by Danny Spanos.

Saw (soundtrack): Saw: Original Motion Picture Soundtrack is the soundtrack for the film, "Saw".  It was released October 5, 2004 by Koch Records.

Screen Play (blog): Screen Play is an online forum focusing on Australian videogame culture.  Between May 2006 and April 2014 Screen Play was a blog in Fairfax Media newspapers The Age (Melbourne), The Sydney Morning Herald, The Brisbane Times and WA Today.  Screen Play was founded by Jason Hill and featured regular contributions by journalist James "DexX" Dominguez.  Both the Brisbane Times and WA Today began mirroring the blog on 26 June 2009.

Phenomenon (soundtrack): The "Phenomenon" soundtrack is a compilation album by various artists released for Reprise Records, who contributed to the music score of the 1996 American romantic fantasy drama film "Phenomenon", starring John Travolta.  The soundtrack features performances by international music stars including Eric Clapton, Bryan Ferry and Peter Gabriel, and went on to be a high-selling soundtrack release.  The single "Change the World", performed by Eric Clapton, which was released off the album became a global hit and helped to promote the soundtrack's sales figures.

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.

Lak 28 Kudi Da: "Lak 28 Kudi Da" ("English": "The Girl's Waist is a 28") is a track by Punjabi artist Diljit Dosanjh, with producer Honey Singh, and features on the soundtrack album to the film "The Lion of Punjab", which also starred Dosanjh.  The track was released digitally in India and globally by Music Waves as part of the album soundtrack on 31 January 2011; the physical release of the soundtrack was made available on Speed Records, India.  Despite its inclusion on the soundtrack release, the song itself does not feature in the film.

Magnolia (score): Magnolia is the score soundtrack to the Paul Thomas Anderson film of the same name.  The score is composed by Jon Brion.  A soundtrack release for the film with original music by Aimee Mann was previously issued in 1999.  Track 9, "Magnolia", appears on said soundtrack, and is the only track from this soundtrack which does so.

Music from the 3D Concert Experience: Music from the 3D Concert Experience is the first soundtrack release by the American trio, Jonas Brothers.  It was released on February 24, 2009, three days before their 's release.  The soundtrack was expected to debut at the top of the charts but debuted at #3 on the "Billboard" 200.  It is their second soundtrack and most recent soundtrack as of November 2009.  As of February 2015, it has sold 189,000 copies in the United States.

Blade Runner (soundtrack): The Blade Runner soundtrack was composed by Vangelis for Ridley Scott's 1982 film "Blade Runner".  It is mostly a dark, melodic combination of classical composition and synthesizers which mirrors the futuristic film noir envisioned by Scott.  The original soundtrack release was delayed for over a decade, until 1994, despite the music being well-received by fans and critically acclaimed—it was nominated in 1983 for a BAFTA and Golden Globe as best original score.  The soundtrack is regarded as a historically important piece in the genre of electronic music, and has been variously described as 'influential and mythical', 'incredible and pristine', 'evocative', and 'the pinnacle of synthesiser soundtracks.'

The Libertine (album): The Libertine: Music for the Film by Laurence Dunmore is the album release of Michael Nyman's score for the 2004 film "The Libertine" directed by Laurence Dunmore.  It is the third release on Nyman's own label, MN Records, and the first to receive distribution in the United States, by Inner Knot Records.  It is his 50th album release overall.  When Naxos Records began distributing MN Records in the United States in 2008, it was included and began appearing in large quantitites in stores.  This is Nyman's last score for a major motion picture to date, and his last soundtrack release, other than compilation soundtracks.

Supporting paragraphs: Saw (soundtrack) Saw (2004 film)
Answer: Leigh Whannell