© Yorick Jansens / ReutersBroken windows of the terminal at Brussels airport are seen during a ceremony following bomb attacks in Brussels in Zaventem, Belgium, March 23, 2016.
The attacker, whose name was not mentioned, had the job from 2009 to 2010.
He "worked for a period of one month for a cleaning company which was contracted by the European Parliament at the time," spokesman Jaume Duch Guillot said in a statement.
According to an EU official, the terrorist is Najim Laachraoui, 25, who, according to prosecutors, blew himself up in Belgian airport.
He is also suspected of preparing suicide vests used by other suicide bombers during November's Paris attacks that left 130 people dead.
The three attacks, which occurred in the city's Maalbeek metro station and in the airport in Zaventem, killed 35 people, including three suspected suicide bombers. Islamic State claimed responsibility for the attacks.
Laachraoui reportedly had a clean criminal record when he applied for the temporary job in the parliament, the spokesman noted.
Explaining why people like Laachraoui manage to slip through the screening process and get hired at places like the EU Parliament, Lode Vanoost, former deputy speaker of the Belgian Parliament, explained in an interview with RT that the badly-paid, temporary jobs go to people from migrant communities. Employee turnover is very high and the vetting procedure, which Vanoost described as "outdated," simply can't follow the personnel flow.
"It's a total mess," he concluded, adding that this is "not typically Belgian," alluding to the fact that French security had also failed to flag the terrorists that committed the Paris attacks in November beforehand.
"Isn't that ironic that we put so much emphasis on security in our society, but the people who actually have to do it [such as security guards] are mainly people who are badly paid, who hardly get a decent salary, decent working conditions. And after that you are surprised?" Vanoost asked, while noting, however, that Laachraoui had not necessarily posed a threat to security back in 2009 and 2010.
Three of the four attackers have already been identified as the brothers Ibrahim and Khalid el-Bakraoui, born in Brussels, and Laachraoui, a Belgian citizen. The fourth attacker is still being searched for by police.
Comment: The man identified as Laachraoui was wearing a glove, most likely to avoid leaving fingerprints in the airport. (Incidentally, the Bakraoui brothers reportedly worked as janitors at the airport.) If so, he didn't intend to die that way. The third man, who was identified as Faisal Cheffou, was later arrested, but then let go. Was he or someone else responsible for remotely detonating explosive devices (in which case, Laachraoui and Bakraoui were dupes and victims of the attack)? Why was he released? Where is he now, and what did he have to say about Laachraoui and Bakraoui, with whom he was walking in the airport?