In the HBO TV series "Oz", where most of the series' story arcs are set in the 'Emerald City' wing of the Oswald Maximum Security Penitentiary (Oz), Christopher "Chris" Keller is an inmate and the central character featured in Tobias Beecher's storyline. Chris is portrayed by Christopher Meloni. In Season 6 of "Oz", Chris is the Oz prison inmate who causes Tobias Beecher's prison parole to be revoked.

Keller (Prisoner #98K514) was convicted in June 1998 of felony murder, two counts of attempted murder, assault with a deadly weapon, robbery, driving under the influence, and reckless driving. He was sentenced to 88 years, up for parole in 50. In February 2002, Chris was then convicted murder in the 1st degree and sentenced to death. His death sentence is overturned in January 2003.

After Beecher was paroled, he showed his gratitude to Keller by helping him appeal his death sentence, which is then overturned. At about the time, Beecher's father is stabbed to death. While Keller's relationship with Beecher is by now somewhat estranged, he tries to show Beecher that he still loves him by killing Franklin Winthrop, the inmate who had murdered Beecher's father to advance in the Aryan Brotherhood.

To ensure that he and Beecher can be together again, Keller asks Beecher to deliver a package of illegal medicine for his dying ex-wife. Beecher eventually agrees. Keller makes an anonymous telephone call to tip off the police, getting Beecher caught and sent back to Oz.

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