At least 20 people have been injured by security forces who opened fire on protesters in the western city of Abdanan, Ilam province.

People in the city poured onto streets Thursday night over the mysterious death of a protester, Bamshad Soleiman-Khani, who was released from prison earlier in the week.

Soleiman-Khani, a 21-year-old mechanical engineering student was reportedly arrested during earlier rallies in the city. Suffering from a headache after his release, he was taken to hospital immediately, but died on Sunday night.

It was not the first time that a protester died only days after being released from prison. The chief justice of the province, Omran Ali-Mohammadi, said Thursday that Soleiman-Khani committed suicide by taking pills, prompting his fellow citizens to hold the protests on Thursday night rebutting what they see as a regime cover-up similar to scores of others before.

In May, Amir-Hossein Tarval-Iman was pardoned and released after eight months of detention but died following a heart attack a few days later. A month earlier, 19-year-old Yalda Aghafazli died after being released from prison without any medical preconditions. Hospital tests indicated a significant amount of narcotics in her blood system, likely forcefully administered while she was in detention.

In November, Arshia Emamgholizadeh, 16, was arrested in East Azarbaijan province for throwing the turban of a cleric. He was kept in prison for ten days and released on bail. He was said to have committed suicide two days later.

Since protests began last year, regime agents have arrested 20-30,000 Iranians.