Eddie did not really kill the girl, he offered the girl as a gift to Senator Norton to bribe him to vote the opposite way, making yakamoto corp unable to get control of microcon and instead eddie's father's kaeratsu can gain control on microcon. eddie was on the floor checking that he received the offer. instead of heading into the secret room, senator and the girl started having sex in the conference room. after having rough sex, senator cuts off her air until she passes out then leaves. then another person sneaks in a few minutes later and strangles her to death.
when all this was captured on camera, ishihara tried to cover it up by having his american associate kill the girl. they would use the tape to blackmail senator norton as leverage so he can vote to make the microcon deal legal for yakamoto corp. they would also replace the tape with an altered tape that replaced senator norton with eddie as the man having sex and the girl jus getting killed through rough sex; framing eddie as the murderer.
eddie expected his father's competitors to go after him, so he called connor and got him assigned to the case the night of the murder. when they found eddie alive in smith's home, so did ishihara's people. eddie gave connor the real disc in exchange for his passport and they try to flee. smith was endangering his family for eddie, so in exchange eddie eludes their group and instead faces ishiharas men alone. he gets killed in the quarrel and smith gets shot, with a bulletproof vest on.
that concludes the interrogation that was going on for the entire movie. afterwards, smith meets up with jingo and connor and reviews the real disc. they barge in on yoshida's meeting with microcon and shows the real disc. ishihara is shamed in his mistake and reveals it was his white associate that murdered the girl. when smith and connor try to confront him, he flees and they give chase. they get confronted by eddie's men who fight with them for a small amount of time to delay them. while they are delayed, more of eddies men runs into the white guy and tosses him into a base of wet cement.
that pretty much sums up the last 20 minutes. smith and connor were forced to be on leave, so everything is pretty much closed now. connor and smith part ways, with connor going to play golf with yoshida-san. smith drives jingo home and they have a couple of minute conversation that ends the movie.
yea it was revealed in the last few minutes of the movie when smith drives jingo home, which is in fact the same place he picked up connor in the beginning of the movie