Bamako - A deadly attack and hostage-taking at a Mali hotel is believed to be the work of an Islamist organisation with ties to an al-Qaeda linked group, investigators said on Monday.Although no-one has yet claimed responsibility for the attack, investigators found phone numbers and addresses on the bodies of the "terrorists" which suggested they belonged to an Islamist group.The hostage crisis, which began early on Friday, ended nearly 24 hours later when Malian troops stormed the Byblos Hotel in the central town of Sevare.The Malian government said four soldiers, five UN workers and four "terrorists" were killed. Among the victims were two Ukrainians, a Nepalese, a South African and a Malian driver, according to the UN mission in Mali.Investigators said there were "strong suspicions" the hostage-takers were from the newly formed Macina Liberation Front (FLM), an Islamist extremist group drawn from the Fulani people from the centre of the country.No formal proof"Investigators found telephone numbers and address on the bodies of the terrorists... which supports the FLM theory," a security source said, indicating that an identity card found on one of the bodies showed he was from the Macina area, in central Mali."At this stage there is no formal proof that it was the Macina Liberation Front (FLM), but strong suspicions point to this group that has been seeking notoriety at all costs," she said.Separately, three Malian soldiers were killed and four wounded on Monday in Diabozo, near Sevare, the government said in a statement.Their vehicle "hit on an improvised explosive device near the town of Diabozo, in Tenenkou department", the statement said. It was not immediately clear who may have been behind the attack.The west African country has seen a surge in jihadist violence in recent months despite a peace deal signed in June.The FLM, which emerged earlier this year, has claimed a number of attacks, some targeting security forces in central Mali.It is considered linked to Ansar Dine - Arabic for "defenders of the faith" - one of the groups that took control of Mali's vast arid north in April 2012.Washington added Ansar Dine to its terror blacklist in 2013, accusing it of close ties to al-Qaeda and of torturing and killing opponents in the north.Mauritanian news agency Al-Akhbar, which regularly publishes jihadist statements, also said the FLM could be behind Friday's attack in Sevare.'Like a warzone'Details of the deadly siege, which began early Friday, emerged on Monday with the family of one of the victims saying he had been sending them messages on WhatsApp during the shootout.Roelof "Jaco" Janse van Rensburg, a South African rescue worker, managed to message his family from the hotel bathroom where he was hiding for hours as the drama played out, his brother-in-law told AFP."He was saying it [was] like a warzone out there," Cobus Smal told AFP, saying the messages had gone on for hours until his brother-in-law's phone battery had died during the evening."Everybody was hiding, they were trapped in their rooms."The family heard nothing until the next afternoon when they were told he was dead.A Malian military source confirmed that foreign special forces had been involved when they stormed the hotel, without giving further details.Back to normalBy Monday, life had returned to normal in Sevare, with several marriages also taking place, although security remained high, with troops in the town and along the road to the regional capital Mopti.The Byblos Hotel was in ruins with bullet-riddled walls, doors torn from their hinges and the ground littered with debris. Sheets and pillows were stained with blood and outside the hotel stood the charred remains of a vehicle, images obtained by AFP showed.Located 620km northeast of the capital Bamako, Sevare is a key staging post on the road to Mali's vast desert north which fell to Islamic extremists in 2012.A French-led offensive routed Islamist groups from their northern strongholds the following year, but entire swathes of the desert region remain lawless.The attack came as the former French colony seeks to implement a June peace deal with armed groups to end ending years of unrest and ethnic divisions.Jihadist attacks have long been concentrated in Mali's north, but began spreading earlier this year to the centre, and in June to the south near the borders with Ivory Coast and Burkina Faso.Two attacks earlier this month in central and northern Mali left 13 soldiers dead.