La Paz Cops - Sorry no money for you guys

La Paz has a reputation for corrupt cops. I had just entered the city, when I saw a cop on his motorbike on the opposite trafic flow, spotting me. He did a 180 and followed me closely. I was absolutely and exactly doing the 30 km/h speedlimit or even slower. I was the only one going that slow and had cars passing on my left at twice the speed. I was also the only one stopping at all those "Alto" signs that stand at almost every crossroad. Nevertheless the guy followed me. Tourist easy target alike, I guess. I almost stopped at green lights just not to give him a reason to pull me over. I did that for some 5 minutes or so, when at a red light he drove by real close in the middle of the two car lane and stopped at the side of my window. He looked at me and gave me that really annoyed look, "Holà, buenas diaz" I said through the open window. No answer, when the light turned green he was speeding it up and passed all the cars that were in line in front of me.