Spain’s National Court heard testimony Monday in an investigation into whether a Spanish company was hired to spy on Julian Assange during the seven years the WikiLeaks founder spent in the Ecuadorean Embassy in London.

The court is investigating whether David Morales, a Spaniard, and his Undercover Global S.L. security agency invaded the privacy of Assange and his visitors at the embassy by secretly recording their meetings. The intelligence that Morales’ company collected is suspected of being handed over to third parties, according to court papers.

Among those set to face the court's questions Monday were prominent Spanish lawyer Baltasar Garzón, who is part of Assange’s legal team; former Ecuadorean consul in London Fidel Narváez; and Stella Morris, a legal adviser and Assange’s partner, who revealed earlier this year that she had two children with him while he lived in the embassy. Staff of the Spanish security company are due to testify on Tuesday.

Assange, whose lawyers filed a complaint at the court to trigger the investigation, is in a British prison after being removed from the embassy last year. He is fighting extradition to the United States, where he faces espionage charges over the activities of WikiLeaks.

The court is conducting an investigation, begun last year, before deciding whether there is evidence of wrongdoing that warrants a trial.

Undercover Global, also known as UC Global, was hired by Ecuador’s government to provide security at the Ecuadorean embassy in London between 2015 and 2018. Its main task was to secure the property’s perimeter, including the deployment of security staff, due to Assange’s presence inside, court papers say.