This is done by blond... she took his bicycle there to fake out his death and lead Ooishi-san to this belief... and him fighting someone before his death... could either be him against blond, or the injection making him see people when they don't exist... how did he got hurt? probably just her after that to fake the scene more... or the injection making him see the ghosts... this is why i hate to have supernatural stuff in the middle of the mysteryge ,_, it could always be "lee magiiccc" ,_,