Del Toro used to deal with Peter, trading guns for drugs. When Peter left Donna, Del Toro picked up with Donna and it left her with a heroin habit. Del Toro lived in a broken-down apartment on the corner of 8th and Pine with hookers and guarded by many men, presumed to be drug addicts as well. Jack Bauer took many if not all of his men out when attempting to reach Del Toro and interrogate him. He was shot in the knee when he concealed information about Madsen.
Background information and notes
In a teaser for 24: The Game, Jack Bauer was shown holding Del Toro over the edge of the subway, saying that if he didn't get the information in ten seconds, he would be killed by the subway train. We last see him screaming after a few seconds, as the train comes closer.
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