Baghdad ? Blood splotches on walls, chains hanging from a ceiling and swords on the killing floor – the artifacts left a disturbing tale of brutalities inside a suspected al-Qaida in Iraq torture chamber. But there was yet another chilling fact outside the dirt-floor dungeon.

Villagers say they knew about the torment but were too intimidated by extremists to tell authorities until now.

Stories such as these – claims of insurgent abuses and the silence of frightened Iraqis – have emerged with increasing frequency and clarity recently as U.S.-led forces push deeper into former extremist fiefdoms and forge alliances with tribes seeking to reclaim their regions.

The reports and tips now pouring in build a harrowing portrait of rule under al-Qaida and its backers: mass graves, ruthless punishments, self-styled Islamic courts ordering summary executions.

Such a lead brought soldiers earlier this month to the hidden room in Muqdadiyah, about 60 miles north of Baghdad, the U.S. military said Thursday. Graffiti on the building proclaimed “Long Live the Islamic State” – a reference to the Islamic governance, or caliphate, sought in Iraq by Sunni extremist groups that include al-Qaida.

Scrawled in white paint above a bed in the torture area was a Quranic phrase in Arabic normally used to welcome a guest. But the context suggested only sadistic mockery: “Come in, you are safe.”

The floor was littered with food wrappers, plastic soda bottles and electric cables that snaked to a metal bed frame, presumably where detainees were shocked, according to the U.S. account of the discovery during a Dec. 8-11 mission.

The rooms “had chains, a bed – an iron bed that was still connected to a battery – knives and swords that were still covered in blood,” said U.S. Army Maj. Gen. Mark P. Hertling, the top U.S. commander in northern Iraq.

Nearby were nine mass graves containing the remains of 26 people, he said.

Villagers knew about the torture site, but did not tell authorities as they were afraid of reprisals from the militants, a local policeman told The Associated Press. He spoke on condition of anonymity as he was still afraid of being targeted by extremists.

He said he thought the chamber had been used for a year.

It was not the first such torture chamber discovered in Iraq. But it serves as a reminder of the extremist grip in parts of Iraq despite growing optimism as violence continues to fall.

And Diyala province – where the grisly discovery was made – remains one of the most volatile regions as U.S. and Iraqi forces struggle to match the clear advances against extremists made in Baghdad and the western desert of Anbar.

The province is mixed between Sunnis and Shiites – often called a “little Iraq” and a remnant of Iraq before sectarian bloodletting partitioned many parts of the country along religious lines. Diyala’s capital, Baqouba, also is the self-proclaimed seat of the insurgents’ caliphate.

“I think that is why al-Qaida wants that province so very much, because it is ‘a little Iraq,'” Hertling said. “It gives them access to Baghdad and it also … is considered their caliphate capital.”