Spain has arrested one of its top police officers after €20 million was found hidden in the walls of his home in an investigation into the largest cocaine bust ever in the country.

Described as discreet and hard-working, Oscar Sanchez Gil was until recently head of the anti-fraud and money-laundering section of Spain’s National Police in Madrid.

Officers arrested him last week along with 15 other people, including his romantic partner, a police source told AFP. The source did not name the romantic partner, who is also a police officer in the Madrid region.

During the raid, police found 20 million euros, or about $21.1 million, in cash hidden in the walls and ceilings of the couple’s home in Alcala de Henares, a city of about 195,000 located about 28 miles east of the capital of Spain.

Officers also discovered one million euros in his office, hidden in two locked cabinets, in bills from 50 to 500 euros, according to the police source.

The couple were charged with drug trafficking, money laundering, corruption and membership of a criminal organization after they appeared before a Madrid court last week, which remanded them in custody, a judicial source told AFP.

Spanish media said the arrests were linked to a cocaine seizure in Algeciras on October 14 from a container ship that had arrived from Ecuador’s largest city of Guayaquil, a drug-trafficking hub. The cocaine was hidden in banana crates. Screens were put up to hide the cocaine, cops said in a press release.

Police said the drug seizure was Spain’s biggest cocaine haul and “one of the biggest seizures in the world”.

The container was destined for a Spanish importer based in the southeastern coastal city of Alicante “which for years had received large quantities of fruit imported from Ecuador,” authorities said. Spanish police said they cooperated with Ecuador’s National Police to intercept the shipment.

Spain, a main gateway to Europe for Latin American cocaine, has cracked down on drug shipments arriving from Latin America. Seizures of cocaine in European ports have reached record levels, the head of Europol’s narcotics unit, Robert Fay, told AFP.

Spain worked with counterparts in June to arrest 40 people in a years-long operation to bust a major drug-trafficking ring. In July Spain participated in a destruction of a major transportation network in Latin America cocaine in Europe by boat, which involved 50 arrests in eight countries. Twenty-six of the detainees were arrested in Spain.

A quick look: The suspicious death of Megan Parra

Trump expected to pick Rubio as secretary of state and Kristi Noem as secretary of Homeland Security

Democrats are playing the blame game after Kamala Harris’ defeat