A Civil Guard report on the violence that allegedly followed last year's Catalan independence referendum describes how protesters "threw paper planes at police vehicles". The description of these events is included in court documents in the case under investigation by the Supreme Court against the pro-independence leaders facing charges of rebellion.
“Lanzaron aviones de papel hacia los vehículos policiales”. Transcripció de part de l’atestat de la Guàrdia Civil que descriu la violència suposadament dirigida contra ells a Catalunya.
— Andreu Van den Eynde (@eyndePenal) 27 de setembre de 2018
The report describes the various rallies in the days following 1st October last year to condemn the police's actions that day. Among these, it highlights the protest in front of the police headquarters on Barcelona's Via Laietana, saying that paper planes were thrown at police vans. According to the officers, this was an example of the "harassment received by the officers" and is used by the accusation to say that there was a "violent uprising".
Imágenes de una de las brutales agresiones separatistas a las fuerzas del orden, mediante el lanzamiento de aviones de papel, que la G.C. hace constar en sus informes. Supongo que esto debe justificar los más de 1.000 heridos del #1O. pic.twitter.com/LhfiqZ5eQv
— Manuel García (@Candeliano) 27 de setembre de 2018
Spanish police also say that protesters shouted chants like "murderers" and "out, out, out, Spanish police".