German police opened an investigation after two teens allegedly controlled a red-and-gold robot that reportedly groped a 16-year-old girl in Cologne. Officers said the incident happened at about midnight on Saturday near a fast-food spot close to the city centre. Police confiscated the robot, which allegedly approached the girl from behind, grabbed her buttocks and made pushing movements before she screamed and ran away. Investigators said the device was found in the boot of a car, where the suspect had placed it. Police also seized two mobile phones belonging to the teens. Renania de Nord-Westfalia police said the robot's owner, 16, and a friend, 19, allegedly transmitted the incident live on social media and posted comments about it. They are trying to establish whether someone deliberately controlled the robot's movements at the time. A photo released by police shows the robot with a black moustache, a gold-coloured chain and a white tank top. In a later Facebook post, police warned that some comments about the case online could go too far and, in the worst case, amount to an offence.