Indonesian police are investigating allegations of torture by dozens of anti-terror officers after video footage showing police abuse emerged last week.

The 14-minute video, released on YouTube, shows members of counter-terrorism unit Densus 88 beating half-naked suspects and shooting one man in the back.

“We are still studying the video and plan to question all officers involved,” National police spokesman Boy Rafli Amar told AFP, adding that the video was filmed in 2007. The source of the video is still unknown.

Amar said the man who was shot had been jailed since 2005 over the beheading of three Christian girls in Poso. His fate is unknown. The others were jailed for more than 10 years over other terror cases, including bombings.

The armed officers, wearing bullet-proof vests and helmets, were identified as members of Densus 88, while several were from the police’s elite Mobile Brigade, AFP reports.

Rights groups have criticized the video and asked the government to review the unit.

“We have many times criticized Densus 88 for using excessive violence and causing the death of terror suspects; we reminded them that Densus 88’s aim was to reveal terror networks, but how can they do that when the suspects are dead?” Bhatara Ibnu Reza, operational director of human rights group Imparsial, told the BBC.

Densus 88 or Detachment 88 was set up after the 2002 Bali bombings to crackdown on terrorism in the country.