The leader of Western Sahara's independence movement, whose presence in Spain has angered the Moroccan government, appeared via video link before a Spanish court on Tuesday to answer allegations of torture and genocide.
Following the hearing, the court ruled Brahim Ghali should not be detained while the investigation continues.
The court said the plaintiffs had thus far failed to prove the rebel leader had committed any crime.
The judge will decide after his preliminary investigation whether there is enough evidence to bring charges.
Ghali's treatment for COVID-19 at a hospital in Spain has soured relations between Madrid and Rabat.
Ghali heads the Polisario Front, a group that is based in southern Algeria and fights for the independence of Western Sahara, which Morocco annexed in the 1970s.
With Ghali considered a war criminal by Rabat, the Moroccan government last month decided to turn a blind eye at its shared border with the Spanish enclave of Ceuta, and allowed thousands of immigrants access to the enclave, much to the anger of Spain's Prime Minister Pedro Sanchez:
"It is unacceptable for a government to say that it is attacking the borders, in this case, Spain's borders, that it is opening the borders so that 10,000 immigrants can enter a Spanish city such as Ceuta in less than 48 hours because of disagreements and differences, discrepancies in foreign policy," Sanchez said on Monday.
Madrid agreed to treat Ghali as a favour to Algeria, its main supplier of natural gas, according to Spain's El Pais newspaper.
Ghali denies charges
Ghali is targeted by two different complaints. One alleging torture and other crimes was brought in 2019 by a Sahrawi activist and Polisario dissident. The magistrate has also re-opened an earlier genocide case, initially launched in 2008, against Ghali and other Polisario members.
Ghali's lawyer said his client denied the charges, which he linked to Moroccan efforts to discredit the Polisario Front. He said he would file a request for the charges to be dismissed.
'Trust has gone'
Eduard Soler Lecha is a Senior Researcher at the Barcelona Centre for International Affairs. He said Spain and Morocco perceive the current crisis, and the future of their relations, very differently:
"If you ask Madrid, Morocco is still a strategic partner...If you ask Rabat, they will tell you that this strategic partnership is broken, that trust has gone, and that unless Spain changes its policy considerably towards Western Sahara, these ties won't be mended."
Watch the full interview with Eduard Soler Lecha by clicking on the media player above.