Al-Abdulmohsen is currently being questioned and prosecutors expect to charge him with murder and attempted murder in due course, the head of the local prosecutor’s office said Saturday.
Reiner Haseloff, prime minister of the state of Saxony-Anhalt, said a preliminary investigation suggested the alleged attacker had acted alone.
City officials said around 100 police officers, medics and firefighters, as well as 50 members of the emergency services, rushed to the scene shortly after 7 p.m. local time on Friday.
Al-Abdulmohsen allegedly entered the market through an entry point reserved for emergency vehicles, police said.
The suspect is a psychiatrist who lived in Bernburg, about 40 km south of Magdeburg.
Originally from Saudi Arabia, al-Abdulmohsen arrived in Germany in 2006 and was recognized as a refugee in 2016.
He ran a website aimed at helping other former Muslims flee persecution in their Gulf countries.
