Associated Press — Associated Press (AP) — Thirty-seven suspected illegal miners who died in the custody of a Nigerian security agency last month suffocated in an overcrowded cell, a government investigation panel said Tuesday.

The deaths have sparked outrage and protests in Nigeria and turned a spotlight on the detention system in the country.

The suspects were arrested by officers of the Nigeria Security and Civil Defense Corps, or NSCDC, a paramilitary agency, and accused of illegal mining in Niger state in September.

The agency initially blamed the deaths on a disease outbreak in the cell, a claim survivors rejected.

Jonathan Kure, the head of the committee set up by the Ministry of Interior to investigate the deaths, said that about 50 male detainees were confined in a space measuring about 20 square meters (215 square feet).

The deaths were caused by “severe overcrowding, unlawful and unsuitable detention conditions, failure of duty of care, disregard of repeated distress warnings, inadequate supervision and wider systemic deficiencies,” Kure said.

The arrests were made without proper planning or consultation with relevant mining authorities, Kure added.

Interior Minister Olubunmi Tunji-Ojo suspended the agency’s Niger state commandant along with officers.

The committee recommended a sum of 30 million naira ($22,000) be paid to each of the bereaved families and 10 million naira ($7,000) each to 41 survivors.

Illegal mining in Nigeria is fueled by a lack of regulation and weak enforcement. Analysts say it funds armed groups.