JOHANNESBURG (AP) — Women’s rights groups in South Africa expressed outrage Thursday and criticized police for perceived failures after charges were dropped against 14 men accused of gang raping and robbing female members of a film crew at an abandoned mine in Krugersdorp, west of Johannesburg.

State prosecutors said there was insufficient evidence against the men to proceed with the case.

The men, believed to be illegal miners, were arrested during a police raid at the mine after at least eight women were attacked and raped while they were filming a music video in July.

Reports of the rapes sparked violent protests in townships around Krugersdorp as community members accused the small-scale miners working in the abandoned mine shafts of committing the crimes.

The protesters also descended on the abandoned mines, blocking the holes the miners use to go underground and burning their makeshift tents and belongings. Miners were apprehended, assaulted and handed over to the police.

Police Minister Bheki Cele called the rapes the “shame of the nation” and police initially arrested more than 80 men before charges were ultimately laid against 14.

However, the rape and robbery charges were withdrawn on Thursday and South Africa’s National Prosecuting Authority (NPA) said DNA results could not link any of the men to the rapes.

“Upon consultation with the complainants in the matter, and evidential material currently at the disposal of the NPA, it became apparent that there is insufficient evidence to proceed with the prosecution,” said NPA spokeswoman Phindi Mjonondwane.

The Commission for Gender Equality, an organization that advocates for women’s rights, called on the police to quickly relaunch an investigation.

“We are completely outraged at these latest developments, which means the police have no idea who committed this crime. They arrested the wrong people, so the real criminals are still out there,” said spokesman Javu Baloyi.

The Sisonke organization, which staged demonstrations at court during the suspects’ appearances, also called on police to act quickly to find those responsible.

Prosecutors said the 14 men are now only facing charges related to immigration offenses as they are suspected to be in South Africa illegally.