The suspicious death of a 17-year-old girl in Tehran is fueling anger among demonstrators who have been opposing Iran's strict dress codes. The deadly protest was triggered by the death of another woman in police custody last month.

The body of Nika Shakarami was found in the yard of a building on September 21. The 17-year-old was believed to have taken part in demonstrations.

Prosecutors said her death has nothing to do with the demonstration. They said the evidence suggests someone pushed her down from a height.

However, Nika Shakarami's mother is pointing the finger at the security authorities. Nasreen Shakarami told a local media outlet that her daughter was killed the same day she went missing in the protests.

The mother also said while she was on the phone with her daughter, she could hear Nika and her friends shouting about security agents as if the girls were running away.

The incident has fueled suspicion on social media that security authorities may have been involved in Shakarami's death.

One of Iran's largest series of protests ignited in mid-September when a 22-year-old woman died after being arrested over how she wore her hijab headscarf. Protesters believe she was beaten by police.