Clues from the thirteenth bomb allowed the police to arrest the first alleged perpetrators, three Moroccans (Jamal Zougam, Mohamed Chaoui and Mohamed Bekkaliand) and two Indian citizens, on Saturday, 13 March. The bomb has been called "the bomb that dismounted the PP version of ETA", and was known to Spanish sources as "Mochila de Vallecas", "Backpack from Vallecas", because its discovery was announced in the Vallecas Police Station on the morning of 12 March. The thirteenth bomb's validity as an exhibit is disputed.