According to Los Angeles law enforcement officials, the discovery triggered the volatile family fight, which ended with Ryan's arrest after he allegedly fired a gun shot.
According to Web site TMZ.com, Griffin had taken the extreme steps after finding his brother unconscious from an apparent drug overdose.
After calling paramedics to the home, Redmond became responsive and claimed he had just been sleeping. Griffin believed his brother had overdosed and chained him to the staircase to prevent him from leaving and buying more drugs.
When Ryan returned home, he apparently became enraged when he tripped over the chain tied to Redmond.
Police officials tell TMZ.com they believe it was Ryan, not Griffin, who initially began swinging a fireplace poker that struck Griffin's pregnant girlfriend Joanna Berry, who called the authorities to the O'Neal home and was later treated in hospital for a cut above her eye.
Reports suggest the altercation escalated and Ryan fired a warning shot into the staircase to scare Griffin.
When deputies arrived on the scene, they found Redmond still tethered and shot video as evidence to document the situation. They also shot video of Ryan's injuries.
Ryan was arrested and charged with assault with a deadly weapon and negligent discharge of a firearm after the fight and his case has been forwarded to the Los Angeles County District Attorney's office. The District Attorney will decide whether or not to file charges against the star.
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