The singer, who toured the world in a career spanning 50 years and came to worldwide prominence when she recorded a song with Freddy Mercury for the 1992 Barcelona Olympic Games, is to face an investigating judge on May 9, the source said.
An official at Catalonia's High Court confirmed that Caballe had been called to testify over a tax case but did not specify a date for the hearing.
Caballe could not be reached immediately for comment.
In October 2012, the singer suffered a minor stroke and broke her arm while in Russia and was flown to hospital in Barcelona.
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An official at Catalonia's High Court confirmed that Caballe had been called to testify over a tax case but did not specify a date for the hearing.
Caballe could not be reached immediately for comment.
In October 2012, the singer suffered a minor stroke and broke her arm while in Russia and was flown to hospital in Barcelona.
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