MUENSTER, Germany (Reuters) - The man who drove a camper van into a group of people sitting outside a restaurant in the German city of Muenster on Saturday acted alone and appears to have had mental health problems, the regional interior minister said on Sunday.

The man killed two people when he ploughed the vehicle into people seated at tables outside the Grosser Kiepenkerl eatery, a popular destination for tourists in the old town of the university city in western Germany. He then shot himself dead.

“We now know it was in all likelihood a lone perpetrator, a German,” Herbert Reul, interior minister of North Rhine-Westphalia, home to Muenster, told reporters.

“There are lots of indications the person in focus had (psychological) abnormalities. This must be carefully investigated,” he said after paying his respects to the victims with national Interior Minister Horst Seehofer and state premier Armin Laschet.

There was no evidence of any link to Islamist militancy and the suspect was not a refugee, Reul said.

The senior public prosecutor in Muenster, Elke Adomeit, said the perpetrator, who German media named as Jens R., was known to police for making threats, damaging property, a hit-and-run traffic accident, and fraud.

“All proceedings (against him) were discontinued,” Adomeit said.

Muenster police chief Hans-Joachim Kuhlisch said investigators had searched four apartments overnight belonging to the man, who was 48.

“You will understand that with four apartments - two in eastern Germany, two in Muenster - we can’t now say conclusively that we won’t find anything,” he said.

However, investigators found no signs of a political motive in their initial searches of the apartments and of several cars and a container belonging to the man, Kuhlisch said.

“COWARDLY AND BRUTAL”

In Berlin in December 2016, a Tunisian whose request for asylum was turned down and who had links to Islamist militants hijacked a truck and ploughed into a crowded marketplace. Twelve people, including the man driving the truck when it was hijacked, were killed.

Police said on Sunday they were still investigating possible motives and forensic investigators were scouring the scene of the attack for clues.

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Seehofer described the attack as a “cowardly and brutal crime”. He, Laschet and Reul laid flowers in central Muenster and paid their respects to the victims of the attack.

“We have again experienced that ... absolute security is unfortunately not possible,” Seehofer said, adding that the government would do everything possible to protect citizens.

The Frankfurter Allgemeine Zeitung reported in its online edition that the man, who it named as Jens R., resided some 2 km (1.2 miles) from the crime scene.

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A 51-year-old woman from the Lueneburg area in northern Germany and a 65-year-old man from the Borken area near Muenster were killed.

Chancellor Angela Merkel said in a statement she was “deeply shaken”. In the months prior to the Berlin assault, Germany suffered a number of small-scale Islamist militant attacks, which some linked to Merkel’s decision in 2015 to open the country’s borders to an influx of migrants, many of them refugees from conflicts in the Middle East.

Saturday’s attack in Muenster came a year to the day of a truck attack in Stockholm in which a suspected Islamist militant sympathizer links killed five people.