Spain's Deputy of Public Prosecutions, José Manuel Maza, signed an order to provincial prosecutors in Barcelona, Tarragona, Lérida and Gerona on Wednesday, instructing them to investigate 712 Catalan mayors for allowing the use of municipal facilities for the independence vote on October 1.

Maza also named the Catalan police, the Mossos—specifically—as the force that would act as judicial police to arrest the mayors "in the shortest period of time possible" if they did not comply with the prosecutor's investigation.

The mayors will be investigated "in relation to alleged acts of coope...