kiev ukrainian judge release son ukraine interior ministry custody wednesday condition appear court require connection embezzlement case tuesday ukraine national anti-corruption bureau nabu detain three people connection suspect embezzlement 521,000 contract supply backpack interior ministry ukrainian media report former deputy interior minister serhiy chebotar interior minister arsen avakov son oleksandr among take custody accord news agency interfax ukraine kiev district court rule oleksandr avakov could release provide appear demand investigators report movements so-called backpack case openly discuss ukraine since 2015 detentions welcome anti-corruption activists sign nabu fulfil mandate investigate high-profile graft case link officials nevertheless detention senior cabinet minister family member also interpret sign possible power struggle within political elite statement interior ministry say case politically motivate avakov say son would fight allegations court neither son firm found single kopeck cent ukrainian budget say facebook individuals suspect allow interior ministry overcharge contract purchase backpack 2015 accord nabu investigation goods deliver time meet requirements set ukrainian interior ministry result state hit loss 14 million hryvnias 521,000 nabu say nabu establish part ukraine western-backed reform drive kiev promise root graft modernize economy exchange billions dollars international fund ukraine backers see failure bring corrupt lawmakers senior officials justice indication authorities may lack commitment eliminate power vest interest ukrainian minister 's son get conditional release graft case