Former public works secretary José López, center, is escort by police near Buenos Aires, after being arrested Tuesday while trying to hide millions of dollars of cash. (Natacha Pisarenko/AP)

For an act of religious charity, it was an odd way to make a donation.

Caught tossing wads of cash early Tuesday over the wall of a convent outside Buenos Aires, former Argentine official José López said he had a good excuse: the money was for the nuns.

López was arrested after neighbors of the convent called police before dawn to report a strange car parked outside and a man throwing plastic bags over the wall. López had climbed over and was apparently trying to stash the money when police arrived and found him in possession of what they called "an obscene amount of cash."

The secretary for public works under former president Cristina Fernández de Kirchner, López was carrying at least $8 million in shrink-wrapped bundles of crispy $100 bills and other foreign banknotes, along with a half-dozen luxury wristwatches and a military-style rifle resembling something out of a Jason Bourne movie.

As the nuns came out of the convent to see López being taken into custody, he reportedly told them he had stolen the money only “to help.”

BEST QUALITY AVAILABLE - In this photo released by the Buenos Aires Province Security Ministry, wads of cash sit in the back of a vehicle shortly after former Public Works Secretary Jose Lopez was caught by police hiding millions at a monastery in the outskirts of Buenos Aires, Argentina, Tuesday, June 14, 2016. Lopez, an official in the government of former President Cristina Fernandez was arrested while trying to hide millions in cash and jewels. (Buenos Aires Province Security Ministry via AP) Wads of cash collected in the arrest of Argentina's former public works secretary José López. (Buenos Aires Province Security Ministry via AP)

The farcical circumstances of López's arrest are not being taken lightly by Argentine prosecutors. On Tuesday night, he was escorted from the police station under heavy security, wearing a bullet-proof vest and a helmet, a sign that Argentine investigators may think they have a valuable potential witness whose life could be at risk.

López worked for 12 years under Fernández de Kirchner and her late husband, former president Néstor Kirchner, overseeing thousands of public-works projects. He currently serves as a lawmaker in the parliament of the Mercosur trade bloc.

Since the end of her second presidential term in December, Fernández de Kirncher has faced growing corruption allegations, and she was indicted last month on charges that she approved currency manipulation schemes at Argentina's central bank. She denies the charges and depicts the inquires as part of a political witch hunt by the government of her successor, Mauricio Macri.

According to Argentine media reports, López has a long relationship with the Kirchners that goes back to the 1990s, and he was close to their former business partner Lázaro Báez, who was arrested in April on corruption charges.