Spain’s public prosecutor ordered an investigation Wednesday into 712 Catalan mayors who have vowed to provide logistical support for a referendum on independence | Lluis Gene/AFP via Getty Images Spain to prosecute 712 Catalan mayors over referendum Catalan officials who help organize the vote risk being charged with disobedience, prevarication, and misuse of public funds.

MADRID — Spain’s public prosecutor ordered an investigation Wednesday into 712 Catalan mayors who have vowed to provide logistical support for a referendum on independence called for October 1 in defiance of a ban by the Constitutional Court.

The prosecutor's move is the latest in Madrid's ongoing judicial offensive against the referendum. The Constitutional Court has already suspended all legislation approved by the Catalan parliament aiming to lay the legal groundwork for the vote; judges are investigating regional President Carles Puigdemont and other officials on charges that could result in prison sentences; and prosecutors have ordered the police to hunt down ballot boxes and all materials related to the vote.

Now the chief prosecutor, José Manuel Maza, has ordered the Catalan regional police to summon the mayors as soon as possible and question them about “suspected acts of cooperation in the organization of the illegal referendum.”

He has ordered police to detain those who refuse to appear before authorities and to prioritize the main cities in Catalonia in their investigations. The inquiry could lead to formal charges against the mayors.

The prosecutor’s order states that all actions aimed at organizing the referendum could constitute crimes of disobedience, prevarication, and misuse of public funds. The latter crime is punishable with penalties of up to eight years in prison.

After formally calling the vote last week, Puigdemont and his deputy Oriol Junqueras sent a letter to all 948 mayors in Catalonia asking for their support to organize the vote.

So far, 712 mayors — representing municipalities that are home to about 41 percent of the Catalan population — have said they will cooperate with the referendum and put public facilities at the disposal of the vote, in defiance of a specific order from the Constitutional Court and warnings from the Spanish government.

Some of those who haven’t lent their support, like Barcelona’s Mayor Ada Colau, have been the target of public protests organized by pro-independence groups. Puigdemont called on citizens to approach their mayors in the streets and ask them whether they will prevent them from voting, leading to complaints from Socialist mayors that they have been the target of threats.

Spanish Prime Minister Mariano Rajoy has said he will do “whatever is needed” to prevent the vote from taking place.