"My brother Barto Pedro Orent-Niedzielski has just passed away. He thanks you for the love and strength you have given him," the brother of Polish-born victim wrote on Facebook.

Barto was critically wounded during a terror attack at a Christmas market in the French city of Strasbourg died from his injuries on Sunday. Barto Orent-Niedzielski was the fifth fatality from mass shooting. 

Orent-Niedzielski and his Italian friend Antonio Megalizzi had blocked the attacker from entering a concert venue during Tuesday's assault. When they saw the attacker, they reportedly rushed to stop him. 

Megalizzi, 28, died from his injuries on Friday.

Orent-Niedzielski and Megalizzi have been credited with preventing a massacre on the scale of the 2015 Paris attack when 90 people lost their lives at the Bataclan. 

Orent-Niedzielski worked as a guide at the European Parliament and also hosted tours around the city, according to Polish news portal wyborcza.pl.

He reportedly worked as a local journalist, danced in a band, sang in a choir and organized the Festival of Comics.