A firearm has been found at the home of the Dutch-Argentinian pilot Julio Poch, the Dutch public prosecutor’s office has told Radio Netherlands Worldwide.

Mr Poch was arrested on Tuesday in Spain, suspected of involvement in the deaths of thousands of opponents of the military dictatorship between 1976 and 1983. The weapon found at his home in the Dutch town of Alkmaar is his service pistol from his time in the Argentinian navy.

The arrest has been widely covered in the Argentinian media. One newspaper referred to the Argentinian-born Dutch Princess Maxima, under the headline ‘Thank you Maxima’.

Under the Argentinian junta, thousands of opponents of the regime were thrown from planes into the sea, in so-called death flights. Mr Poch is suspected of having piloted such flights. His past came to light because in 2007 he boasted about his actions to colleagues at Dutch airline Transavia, saying he had no regrets. The colleagues informed the authorities.

Argentina has applied for Mr Poch’s extradition. If convicted, the 57-year old pilot may be sentenced to life imprisonment.

The Dutch conservative VVD party called on the government to account for the fact that the Dutch intelligence service failed to raise questions about Mr Poch’s past earlier. The service screens pilots before they are employed. However, Mr Poch has been working for Dutch airline Transavia for 20 years.

Spanish interior ministry footage of the arrest of pilot Julio Poch in Valencia: