The death of a suspect after apparently being raped with a bottle in custody has cast shame on Russia\'s police, the interior minister said Thursday, as calls mounted for top officials to resign. Activists have called for the entire Russian interior ministry leadership to quit over the horrific death of 52-year-old Sergei Nazarov after he was arrested in the city of Kazan in the mainly Muslim Volga region of Tatarstan. Russia\'s Interior Minister Rashid Nurgaliyev acknowledged that the incident on Saturday -- which resulted in Nazarov dying of a ruptured intestine after being abused with a champagne bottle -- amounted to a betrayal of police values. \"What should you do with a betrayal?\" Nurgaliyev, a former KGB agent who is one of the closest cabinet allies of Russia\'s leader Vladimir Putin, told an emergency meeting in Moscow in his first comments on the incident. \"Betrayal -- that\'s what the Kazan tragedy deserves to be called. No-one has a right to take away the most important -- life,\" Nurgaliyev told the interior ministry staff in comments carried by Russian news agencies. \"Those who have betrayed the interests of their service and besmirched the honor of their uniform are a disgrace, above all for their superiors who have allowed such situations within their teams.\" Recognizing the gravity of the incident, the authorities have reacted with a speed unusual in Russia. But Nurgaliyev also appeared to be resisting calls for harsh sanctions against higher-ranking officials. Nurgaliyev said he had fired the head of the Dalny police station in Kazan where the attack took place, Sergei Yefremov. Tatarstan police chief Asgat Safarov received a reprimand. On Wednesday, investigators brought criminal charges against four police officers from the Dalny police station. The four -- all in their mid-20s -- were taken into custody but deny the charges, police said. Another officer was detained earlier this week and fully admitted his guilt. \"The question arises: why such young police officers from the Dalny police station who had worked there between six months and three to four years, committed such a savage act,\" Nurgaliyev was quoted as saying. Police have not released details of the crime but human rights activists said Nazarov had been raped with a champagne bottle and later died of a ruptured intestine. Safarov said all employees of the Dalny police station would undergo re-certification and polygraph tests. Vladimir Ovchinsky, the former head of the Russian bureau of Interpol, said Nurgaliyev -- who has so far weathered the social discontent over the conduct of his staff -- should himself be let go. \"The entire interior ministry leadership should resign, otherwise the system will not change,\" he told Echo of Moscow radio. After Nazarov\'s death, several more Russians complained of harassment by police from the Dalny station. Dmitry Kolbasin, head of the Agora inter-regional rights organization, said earlier this week rights campaigners were now looking into seven more complaints. In Kazan, activists Thursday held a picket outside the regional police headquarters protesting police abuse in the city. The behavior of the security forces is seen as one of Russia\'s biggest scourges due to widespread corruption and iron-fisted tactics. Outgoing President Dmitry Medvedev in late 2009 ordered an overhaul of the country\'s police forces even ordering the change of name from \"militsia\" to \"politsia.\" A recent survey by the independent Levada Center pollster found however that 72 percent of the population did not think the change of the police force\'s name had any positive effect. President-elect Putin promised during his election campaign in January to end police repression and make government more accountable in what was seen as a concession to protesters challenging his rule.