Last month Mrs Fernandez's former planning minister was arrested.
Amado Boudou has denied any wrong-doing.
The three charges against him refer to 2009, the year when he was promoted from heading Argentina's social security administration to become Mrs Fernandez's economy minister.
He became vice-president in 2011, when she was re-elected.
Mr's Fernandez's former Planning Minister Julio de Vido was arrested on25 October, three days before mid-term elections.
Mrs Fernandez herself is also facing corruption charges but has immunity from prosecution since being elected as a senator in the October polls.
She was indicted last year on charges that she and her public works secretary, Jose Lopez, embezzled money meant for road projects.
Mr Lopez was arrested last year after he was caught trying to hide bags of cash in a Catholic convent.
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