The perpetrators of the bombing outside the National Cancer Institute in the Egyptian capital likely used the Telegram messaging app to communicate in carrying out the attack, an audio recording revealed on Friday. In the conversations, a man whose nom de guerre is Mohammed Aleesh and someone called Ibrahim Khaled, identified as the brother of the perpetrator behind the car bombing, are heard discussing the whereabouts of the attacker. “I haven’t been able to contact him,” Khaled is heard telling Aleesh about the attacker. The Egyptian interior ministry said Friday that the bomber was a member of Hasm, an armed affiliate of the banned Muslim Brotherhood, and identified him as fugitive 24-year-old Abdel Rahman Khaled. "This was confirmed following the DNA testing of the remains that were found at the site of the accident and based on the comparison with members of his familys (DNA)," a ministry statement said. Egyptian security forces killed 17 "terrorists" during an operation against the suspects in the car blast, the ministry announced. The ministry said the 17 killed belonged to Hasm. It released a series of images and video depicting some of the militants and assault rifles found in their hideouts. The deadly collision happened just before midnight Sunday, when a speeding car packed with explosives drove against the traffic and crashed into three other vehicles outside the Cancer Institute. According to the health ministry, at least 20 people were killed and 47 others injured in the collision. Telegram has become the most widely used app of its kind by terrorists, an expert on extremist groups, told Asharq Al-Awsat. Khaled al-Zaafarani said that unlike Twitter and Facebook, which have shut down thousands of accounts tied to extremist organizations for violating company rules, Telegram has let militants operate without fear of being traced. Amro Abdelmenhem, another expert, said that “around 20,000 to 50,000 terrorists have dropped Twitter in favor of Telegram.” The extremists seem to be able to operate uninterrupted on Telegram, he added.