moscow russian opposition activist ivan skripnichenko die attack man angry oppose vladimir putin month late nobody arrest family see autopsy authorities say probably die heart disease assault 36-year-old father-of-two one grow number vicious attack opposition figure run-up presidential election march putin incumbent widely expect contest activists believe putin kremlin hand attack include caustic liquid throw victim eye car set alight one case activist bash head iron bar critics say way authorities handle case rare anyone arrest nationalist group say carry attack openly boast activities show best turn blind eye bad tacitly condone violence yulia latynina journalist critical authorities force flee russia summer faeces throw car torch noxious gas pump home skripnichenko death part dangerous trend accuse authorities lose control violent extremists responsible splash antiseptic people face pour shit people beat activists puncture tire burn something sooner late someone burn alive die fight latynina say radio show murder accord skripnichenko family unidentified man accost late aug. 15 stand makeshift memorial slay opposition leader boris nemtsov kremlin bridge rally point government critics nemtsov shoot dead spot 2015 chechen gunman one modern russia high-profile kill love putin man ask skripnichenko putin girl love activist parry man knock skripnichenko cap grind victim rise pick punch hard face break nose skripnichenko hit head pavement fell attacker kick lay prone mikhail silich activist skripnichenko time attack confirm family account attack skripnichenko leave hospital tell activists think would ok. family say go different hospital week late get nose reset begin feel unwell canteen come home day phone next morning tell die family activists say authorities investigate death properly investigators neither identify arrest skripnichenko attacker open criminal case dead man family say obtain autopsy report cite procedure moscow investigative committee handle matter tell skripnichenko widow olga would need wait 40 days get report committee respond reuters request comment progress case despite attack take place sight kremlin wall spot nemtsov gun two half years early investigators say cctv footage ilya novikov family lawyer say hard believe cause death question investigators preliminary conclusion die heart disease skripnichenko sister nastya say doctor examine brother say appear suffer serious head wound yet skeptical die heart problems suspect attack trigger problems take time unfold brother never complain heart problems tell reuters say doctor give clean bill health check-up recently spring brother cross-country ski fly glider parachute jump cycle semi-professional level absolutely link brother death attack russia liberal opposition seat parliament scant hope mount serious challenge putin next year though alexei navalny opposition leader fit traditional liberal mould try make run country western sanction 2014 annexation ukraine crimea support pro-russian separatists eastern ukraine pro-kremlin politicians often cast anyone critical authorities enemy within critics say rhetoric fuel attack opposition carry feel sense impunity rarely punish navalny become temporarily blind one eye april caustic liquid throw soon afterwards pro-government tv channel broadcast footage navalny attacker run away scene blur face opposition activists identify man member radical group investigators say enough evidence prosecution another incident nikolai lyaskin navalny ally hit head iron bar moscow last month assault navalny say design turn invalid police detain suspect open criminal case issue statement say suspect tell lyaskin victim pay assailant stage attack police release suspect 48 hours condition disclose spot skripnichenko attack favorite target nationalists dislike makeshift shrine nemtsov former deputy prime minister turn putin critic pro-western traitor sometimes trash shrine pick fight defenders serb radical nationalist group vandalize memorial several time apartment block moscow nemtsov live serb leader igor beketov tear plaque activists hang honor nemtsov state tv report incident complain opposition use nemtsov name various purpose give beketov air time explain grievances outside apartment block skripnichenko family lawyer novikov become embroil fist fight beketov serb members rip photo nemtsov serb pelt target faeces antiseptic urine smash cake navalny face deny caustic liquid attack also hint throw faeces latynina tamara lugovykh activist know skripnichenko say fear authorities everything link death politics interview reuters seven activists say attack chime regular intimidation face saw parallel investigation nemtsov murder convict group chechens fail identify order kill real blood spill spot meter apart say activist andrei margulev bridge shrine portrait skripnichenko display next nemtsov ivan plan children wife sergei kireyev activist know say anything happen bridge rule 'no rule russian activist 's death symbol pre-election violence