One of the perpetrators in last month's terrorist attacks on Brussels twice held a summer job as a cleaner in the European Parliament several years ago.
More than 30 people died in triple bombing attacks on the Belgian capital on March 22.
The perpetrators blew themselves up in the city's international airport and an underground station near the Brussels headquarters of the European Union's main institutions.
"Seven and six years ago, one of the perpetrators of the Brussels terrorist attacks worked for a period of one month for a cleaning company which was contracted by the European Parliament at the time," spokesman for the organisation Jaume Duch said on Wednesday.
"As a student, he held a summer holiday job cleaning at the parliament for one month in 2009 and one month in 2010," he added.
The cleaning firm had submitted proof that the perpetrator - who has not been identified - had no criminal record at the time.
Three of the four attackers have so far been identified: Brussels-born brothers Ibrahim and Khalid El Bakraoui, and Najim Laachraoui, a Belgian national.
They all died in the attacks, while a fourth suspect is still on the run.
