In a ruling seen by AFP, the judge asked police to investigate the top members of Puigdemont's PdeCat party, as well as those of the far-left ERC party which tops opinion polls. Members of two grassroots separatist associations, Omnium Cultural and the Catalan National Assembly will also be scrutinised.
Among those he asked be investigated is Marta Rovira, head of the ERC's list for the regional election in Catalonia slated for December 21st.
The judge is targeting members of a "strategic committee" allegedly put in place to achieve independence for Catalonia. Its existence is mentioned in a document found during a police search of the home of the right hand man of the region's ousted vice president Oriol Junqueras.
That committee was made up of Puigdemont, Junqueras, the leaders of the two grass roots separatist associations and the secretary generals of the separatist parties, a post occupied at the time in the ERC by Rovira.
The judge's decision means Rovira risks being charged and remanded in custody as has already happened to Junqueras, the head of the ERC.
Judge Pablo Llarena is investigating whether there was conspiracy to declare independence for Catalonia in a "violent" way, which would constitute the crime of "rebellion" that carries a sentence of nearly 25 years in jail.
The probe is also looking into the possible crimes of "sedition", which implies a "public action accompanied by disorders" aimed at preventing laws from being respected, which carries a punishment of up to 15 years in jail.
So far 22 people are under investigation: the 14 members of Catalonia's ousted regional government, the separatist head of the Catalan parliament, Carme Forcadell and five top members of her office, as well as the heads of the Catalan National Assembly and Omnium Cultural.
Four of them, including Junqueras, remain in custody.
Spain's central government dismissed the regional Catalan government and called the December 21 election after the region's parliament on October 27th declared independence.