Several of Mr Puigdemont’s ministers in his regional administration were arrested for organising the vote and jailed.
Efforts by Spain’s supreme court to extradite Mr Puigdemont from Belgium, where he served as a European MP until earlier this year, have so far failed.
Unlike others who were involved in the secession attempt, Mr Puigdemont was not eligible for amnesty under a law passed in May, because the supreme court upheld an arrest warrant for embezzlement, a charge he denies.
Waning support
Many in the crowd of thousands who gathered near the parliament building to welcome Mr Puigdemont on Thursday had hoped his return would help build momentum towards independence, which has lost support in recent years.
Pablo Llarena, a supreme court judge, demanded formal explanations on Friday from the police and Spain’s interior ministry of how Mr Puigdemont was allowed to escape.
Spain’s Left-wing government, which has been supported by Mr Puigdemont’s Junts per Catalunya party and agreed to an amnesty, said Thursday’s failed police operation was entirely the responsibility of the Catalan authorities.