Alberto Laplaine Guimarães, Secretary-General of Lisbon City Council, is one of four people arrested in Operation 'Lúmen', which is investigating alleged economic crimes, including corruption, in public contracts for Christmas lights. The investigation focuses on suspected favouritism towards the company Castros Iluminações Festivas, with searches conducted across 10 municipalities. The suspects, including a business administrator, an employee, an association president, and a public official, are accused of active and passive corruption, economic participation in business, abuse of power, and criminal association, involving contracts worth approximately 8 million euros.