A man has been detained after driving his car into a crowd of people in western Berlin, killing a teacher and injuring 14 children who were on a school trip, police have said. The man drove into people on a street corner before getting the car back on the road and crashing into a shop window further on. Berlin police said the schoolchildren and their teacher were visiting the capital from the central German state of Hesse. “Their teacher died at the scene,” Berlin police wrote on Twitter. “Their loved ones have been informed and are being cared for.” Authorities are trying to determine whether the man, identified as 29-year-old German-Armenian who lived in Berlin, deliberately drove into pedestrians or whether it was an accident, possibly caused by a medical emergency. Berlin’s top security official, Iris Spranger, said posters were found in the man’s car “in which he expressed views about Turkey” but refuted an earlier report from the Bild tabloid that a letter of confession had been found in the car. A criminal investigator was cited anonymously in Bild as saying the crash was “in no way an accident”, but that the driver – named as Gor H – was “running amok, an ice-cold killer”. Six people have sustained life-threatening injuries and another three have serious injuries. After steering his silver Renault Clio into a crowd of people on the pavement at about 10.30am, the man had returned to the road before again mounting the pavement and finally crashing into the shopfront window of a branch of the cosmetics chain Douglas. The driver was detained after being restrained by passersby near the site of the crash. The man was known to police for property offences, which can include burglary or theft, but not for holding extremist political or religious views, reported Bild. The incident took place on Wednesday on a road adjacent to Breitscheidplatz square, the scene of a fatal attack on 19 December 2016, when Anis Amri, a rejected Tunisian asylum seeker with Islamist links, hijacked a truck, killed the driver and then ploughed it into a crowded Christmas market, killing 12 more people and injuring dozens of others. Concrete barriers were subsequently installed around the square to prevent similar terror attacks. Earlier this year the Berlin senate had announced proposals to remove the bollards and instead ban cars from the northern side of the square. “We don’t know whether this was a deliberate act or a traffic accident,” a police spokesperson told the Berlin newspaper Tagesspiegel. “We have detained the driver and are shedding light on the matter.” About 130 police officers and 80 fire service quickly arrived at the scene and closed off streets surrounding the site. The actor John Barrowman posted a video from the scene on Twitter, in which he described seeing what appeared to be a car deliberately driving into crowds of people. “There’s lots of police, there’s a dead body in the middle of the road, there’s a lot of people walking with limps and injuries.” Barrowman, known for his appearances in Doctor Who and Torchwood, said he saw a car mount the pavement outside an Italian restaurant on the corner of Rankestrasse and Tauentzienstrasse, then drive back on to the road before again mounting the pavement further down. The Berlin mayor, Franziska Giffey, said she was “deeply shocked” by the incident and that authorities were keeping an open mind about possible motives. She said the crash brought back “terrible memories” of the Breitscheidplatz truck attack. The district mayor of Charlottenburg-Wilmersdorf, Kirstin Bauch, said the scenes reminded her of an incident in February 2016, when a speeding driver taking part in an illegal race crashed into a Jeep at a crossing with the same road, killing the pensioner behind the steering wheel. “We have to do everything to ensure that such grave accidents can be avoided in the future,” she said.