Portugal’s Antonio Costa, who unexpectedly resigned as prime minister on Tuesday amid a probe into possible government corruption, apologized on television for envelopes of cash seized in his chief of staff’s office as part of the ongoing investigation.

“The seizing of envelopes with large quantities of money in the office of Vitor Escaria is, more than a betrayal of my trust, something that embarrasses me deeply before the Portuguese, and so I say sorry,” Costa said on Saturday night from his official residence in Lisbon.

Escaria was detained on Tuesday morning as police raided government offices, and several Portuguese media outlets reported that police found €75,800 ($81,000) in his office. His lawyer, Tiago Rodrigues Bastos, told television channel TVI on Thursday that the cash had nothing to do with the case and was related to his client’s professional activity before he became the prime minister’s chief of staff.

Costa dismissed the chief of staff earlier this week after finding out about the cash.

The corruption investigation is related to lithium exploration concessions in northern Portugal, a hydrogen production project and a data-center project developed by a company called Start Campus in Sines, south of Lisbon.

References made by suspects about Costa’s intervention to “unblock” certain procedures will be assessed in an inquiry at the Supreme Court of Justice, the prosecutor said in a statement on Tuesday.

All the projects being developed in Sines, namely the data center, have been required to meet environmental rules, Costa said on Saturday. He reaffirmed that “nothing weighs” on his conscience and that the government will fully cooperate with judicial authorities.

“Governments have the duty to attract corporate investment,” Costa said, adding they also have to fight bureaucracy and expedite licensing. “It’s very important for the country that we continue to attract investment.”

Read more: Who Will Lead Portugal Now? Turmoil Starts Race for Premiership

Costa said he isn’t afraid of any downgrade to Portugal’s sovereign rating, saying the country has solid public finances.

Diogo Lacerda Machado, a lawyer who Costa once called his best friend, was also detained on Tuesday. Machado hasn’t worked in the prime minister’s office for many years and had no mandate from Costa for anything, the outgoing premier said on Saturday.

“The reality is a prime minister doesn’t have friends. And the longer he’s in office, the fewer friends he has,” he said.

Costa, 62, said the investigation will last a long time and with “great probability” he will never hold public office again.

President Marcelo Rebelo de Sousa on Thursday called an early election for March 10, adding that the prime minister’s resignation will formally take effect in early December. Costa has been prime minister since 2015.

Read more: Bank of Portugal to Assess Centeno After He Was Proposed as PM