Earlier, on New Year's Eve, an envelope containing a suspicious powder was delivered to the house of Theo Francken, a former secretary of state for migration.
After the incident, the politician and his family had to spend several hours in quarantine until the powder was confirmed harmless.
Following this, a suspicious envelope was sent to the Palace of Justice of the city of Louvain — the powder also proved to be harmless.
Later on Thursday, another politician, the chairman of the Christian Democratic and Flemish party (CD&V) Wouter Beke, received a similar letter.
The chairman posted photos of the opened envelope and two civil defence officers in chemical protection suits on social media.
Een brief met wit poeder gericht aan mezelf gekregen op partijhoofdkwartier @cdenv. Blijkt vals alarm te zijn. Tonnen respect voor het werk van politie en civiele bescherming, die dit alles enorm professioneel en nauwkeurig aanpakten. pic.twitter.com/IzvMeVvOLD— Wouter Beke (@wbeke) January 3, 2019
Law enforcement agencies have not yet reported whether these cases will be combined in a single investigation, or if they have identified a link between the string of letters.