Armed with an antique revolver and posing as a prison chaplain, he managed to make it into the building where former Popular Party treasurer Luis Bárcenas lived before being put in jail.
Olivares convinced Bárcenas' wife and son he needed to carry out a report on Mr. Bárcenas, who has been remanded in custody at Madrid’s Soto del Real prison since June awaiting corruption charges.
Once the fake priest had managed to gather family members and their maid in the living room, he pulled out the revolver and demanded they hand over “ a pen drive to oust the government”.
Olivares, who according to El Mundo had psychological problems and a criminal record, was after the flash drive allegedly containing details of all the under-the-table payments made by Bárcenas to Popular Party members – a corruption scandal which has made Spanish headlines for the past year.
The disturbed man from the town of Cuenca tied up the hands of all three victims and held them hostage for over an hour.
Bárcenas' son Guillermo was able to break free from the shackles and restrained the man while his mother cried out for help.
A neighbour heard the screams and called police to the address on Madrid's Príncipe de Vergara Street.
Spanish police later confirmed the pre-Spanish Civil War gun Olivares was loaded only with blanks.
Spain’s El País newspaper published an extract from a letter Olivares wrote to regional daily El Diario de Castilla-La Mancha in 2011, in which he slammed Spain’s secretary general María Dolores de Cospedal for “cutting welfare benefits” to people with physical and mental problems.
“Disabled people in Spain have to live on €11 ($15) a day," he wrote.
"You promised there wouldn’t be spending cuts in your electoral campaign and you lied to us."