Berlin - A German journalist who witnessed the Nice attack said he saw a motorcyclist chase the killer truck and try to enter the cabin, but fall and end up under the wheels."I stood on the balcony, right on the Promenade des Anglais, and saw how people celebrated there, and how suddenly a truck drove through the crowd," Richard Gutjahr, 42, who shot smartphone video footage of the bloody Bastille Day rampage, told AFP on Friday."Surprisingly, he drove very slowly, not fast, he drove slowly and he was chased by a motorcyclist," recounted Gutjahr by telephone."The motorcyclist attempted to overtake the truck and even tried to open the driver's door, but he fell and ended up under the wheels of the truck."Gutjahr, a freelance journalist, said he also saw two police officers open fire on the truck."Then the driver stepped on the accelerator and the truck sped up, accelerated and drove in a zig-zag course into the crowd."In the next 15 to 20 seconds there were shots from several guns. I don't know who shot at whom."After that, "the panicked crowd ran in all directions. Those who could save themselves ran into the hotels, or sought security in the hotel entrances", he said."Right afterwards I personally saw 12 dead bodies, and it was already clear there would be more."