kiev ukrainian prosecutors say friday investigate case could involve head national anti-corruption bureau late merry-go-round law enforcement officials take action prosecutors check audio record man read wiretapping transcript unknown persons could constitute illegal share classify information try establish whether voice belong bureau director artem sytnyk contact comment spokeswoman bureau say sytnyk travel abroad ukraine political leaders want convince international backers serious tackle entrench corruption make limit progress delay billions new loan investigation possible disclosure secret document register general prosecutor yuriy lutsenko say televise brief confirm document status secret confirm do law enforcement official problems law say bureau know acronym nabu sister anti-corruption agency know nazk set pro-western leaders take charge ukraine 2014 follow wave unrest escape exile kremlin-backed former leader lutsenko statement cap week allegations fly around different agencies monday senior prosecutor tell reuters senior political leaders try bury corruption investigations change criminal code would result nabu overload case work tuesday nabu say open case nazk allegations whistleblower also accuse president petro poroshenko office exert improper influence agency president office deny allegation friday well prosecutors announce investigation nabu nabu say open case october lutsenko behest court give detail investigation investigation continue nabu spokeswoman svitlana olifira tell 112 channel lutsenko case conclusions task check facts lutsenko dismiss case illogical say concern whether declare two park place belong adult son online registry officials income property confident legality position say conflict nabu general prosecutor office nothing new august 2016 prosecutors raid nabu offices late interrogate two nabu officials spark protest anti-corruption campaigners lutsenko say infighting agencies unacceptable seem healthy cooperation law enforcement body destabilize say ukraine prosecutors open case inter-agency conflict escalate