Two persons were arrested on Monday in connection with Bangladesh’s worst terror attack at a cafe here in which 22 people, mostly foreigners, were brutally killed by suspected ISIS militants, as authorities stepped up probe into the international links of the hostage-takers.Inspector General of Police (IGP) AKM Shahidul Haque, however, did not disclose the identities of either of the detainees or where they were being kept.He said they were both physically unwell and will be quizzed after their condition improves.‘One of them is in hospital, the other is in custody,’ he said.Earlier, Prime Minister Sheikh Hasina and the Bangladesh Army said one terrorist was captured alive from the site of the attack. However, the identity of the suspect was not disclosed.‘They (attackers) may have some contact with international terrorist groups,’ he said.Islamic State has claimed responsibility for the killing of the 20 hostages and two police officers during the 12-hour siege that ended after the army stormed the Holey Artisan Bakery popular with expats in the diplomatic zone here, killing six attackers and capturing one alive.Hostages who were killed include 19-year-old Indian girl Tarishi Jain. Nine Italians, 7 Japanese, one American of Bangladeshi origin, and two Bangladeshis were also among the people who were killed.‘You have seen the pictures of the slain militants supplied to the media, we have found out the background of four of them,’ a senior police officer, familiar with the investigation, told PTI, preferring anonymity.