'No rules' - Russian activist's death a symbol of pre-election violence

Russian opposition activist Ivan Skripnichenko is seen at the site of the assassination of Kremlin critic Boris Nemtsov in central Moscow, Russia June 22, 2017. Courtesy nemtsov-most.org/Handout via REUTERS

MOSCOW (Reuters) - Russian opposition activist Ivan Skripnichenko died after being attacked by a man angry he opposed Vladimir Putin. Over a month later, nobody has been arrested, his family can't see his autopsy, and authorities say he probably died of heart disease.

The assault on the 36-year-old father-of-two is one of a growing number of vicious attacks on opposition figures in the run-up to a presidential election in March which Putin, the incumbent, is widely expected to contest.