German investigators said Tuesday they suspected an Islamic extremist motive behind a knife attack last week by a Somali man that left three women dead in the southern city of Würzburg.

“The Bavarian Central Office for Extremism and Terrorism has taken over the probe because an Islamist motive is likely,” a joint statement from Bavarian state prosecutors and the state crime investigations office said.

A 24-year-old man on Friday went on a knife rampage in Würzburg, Bavaria, stabbing three women to death and leaving six other people seriously injured.

The suspect, a Somali who arrived in Germany in 2015, struck in the city centre on Friday evening, first at a household goods store before moving on to a bank.

Read more: The Local