ISTANBUL — Turkey’s police and intelligence services may have ignored a wave of warnings about potential suicide bombers from the so-called Islamic State that could have prevented the deadly blasts in Ankara that killed almost 100 people last weekend. And many of those warnings centered on a teahouse about a 90-minute drive from the Syrian border that was known to be a way station, or worse, for ISIS recruits.

Critics say the authorities’ refusal to move against members of ISIS cells in the country amounted to covert support for the jihadists. “We are not talking about failure here, but about intent,” said opposition lawmaker Veli Agbaba. “People we identified months ago are now killing our young. There is only one explanation: [the government] not seeing ISIS as a terrorist organization.”

Turkey frequently has been accused of supporting radical Islamic groups in neighboring Syria in the hope that rebels will bring down President Bashar al-Assad. The government refused to help Syrian Kurds break a siege by ISIS in the northern Syrian city of Kobane last year and waited until July to join the U.S.-led military alliance against ISIS. Since then, Turkish warplanes have conducted far more airstrikes against Kurdish rebels than against ISIS positions.

Ankara says it regards ISIS as a threat and denies providing weapons to any group in Syria. Prime Minister Ahmet Davutoglu told a television interviewer on Thursday that he and President Recep Tayyip Erdogan were the prime targets of ISIS online threats. “They even issued a killing order,” he said. “They declared Turkey a war zone.”

But critics say relations between Ankara and ISIS are much cozier that Davutoglu’s statement suggests. “Until this day, they support and encourage the ISIS barbarians, give them money and weapons,” Selahattin Demirtas, leader of the Democratic People’s Party (HDP), said about government leaders. Supporters of the HDP, Turkey’s biggest Kurdish party, were among the targets of the Ankara bombers.

Following a deadly ISIS suicide attack in the city of Suruc close to the Syrian border in July, Agbaba’s Republican People’s Party (CHP), the biggest opposition bloc in Turkey’s parliament, prepared a report warning authorities of ISIS cells. Nothing happened.

Even back then, news reports drew attention to the “Islam Teahouse” in the town of Adiyaman in eastern Turkey. The teahouse, run by Yunus Emre Alagoz, was known in the city and beyond as a recruiting place for ISIS. Visitors described ISIS flag on the walls.

According to news reports that same Yunus Emre Alagoz, 25, has been identified one of the two suicide bombers who killed 99 people in Ankara last Saturday. His brother, Seyh Abdurrahman, is known as the suicide bomber of Suruc, where more than 30 people died. Both brothers traveled to Syria in recent years, became ISIS members, and learned how to build bombs.

Another regular in the “Islam Teahouse” was Omer Deniz Dundar, the second Ankara bomber. His father told Turkish media he had gone to the police numerous times to warn them about the danger posed by his son and to save his child. Authorities did not act. They also remained passive when Hatice Gonder, a woman from Adiyaman, went to the police to talk about what she saw as radical Islamist tendencies in her son, Orhan. The young man went on to bomb an HDP election rally in June, killing four people. Orhan Gonder had also been to the “Islam Teahouse”.

Journalist Ezgi Basaran used her a column on the Radikal news website in July to provide details about who frequented the “Islam Teahouse” and warned of possible ISIS attacks from members of the group of extremists who met there. “Youths go to Syria from Adiyaman to become jihadists,” she wrote. “Doesn’t the state know what we know?”

Opposition lawmaker Agbaba said it had been obvious for everyone that Adiyaman had been used as a base for ISIS. “But, strangely, the police did not see this.”

The teahouse eventually was closed down after pressure from worried parents—but not because it had served as an ISIS lair, because it did not have a proper license.

Despite being well known by authorities, Alagoz and Dundar were able to travel to Ankara last week and blow themselves up in the midst of a peace march by Kurds and leftist organizations. The Hurriyet newspaper reported the pair traveled openly, even stopping for breakfast at a restaurant in Ankara.

President Erdogan has acknowledged failures by police and intelligence services, and three high-ranking officers of police in Ankara have been suspended. But Erdogan rejected demands for the interior and justice ministers to resign.

Even in the wake of the Ankara bombing, the government is reluctant to move decisively against ISIS supporters, critics say. Prime Minister Davutoglu said law enforcement agencies had a list of the names of potential ISIS suicide bombers on the loose in Turkey. But there have not been any arrests.

“In a country with the rule of law, you cannot arrest them until they act,” he said. Given that Turkish journalists are jailed because they criticize the president and that police regularly clamp down on anti-government protesters, that statement seemed odd to some. “Suicide bombers go free, but you land in jail if you throw an egg,” said the newspaper Sozcu.