What do Boston marathon attacks, Charlie Hebdo and Brussels attack have in common?

When two explosions ripped through Belgium's Zaventem Airport on Tuesday, March 22 the incident sent shock waves across the world. It was termed as a attack on Europe.

While Islamic State claimed responsibility for the attack, many feel that the attack was in retaliation for the arrest of Paris terror suspect Salah Abdeslam, who was captured in Belgium last week.

Post the Brussels attack, police officals were swift and released a CCTV footage of the suspected attackers. However, by Wednesday, March 24 police were able to identify two of the suspects as brothers Khalid and Brahim El Bakraoui.

This however brings us to two more incidents of terror. What do the Boston marathon bombings, Charlie Hebdo attack and Brussels attack have in common? All these attacks were carried out by brothers. Here is a look at the three incidents which involved brother terrorists:

Brothers El Bakraoui had a criminal past

On Wednesday, Belgian state broadcaster RTBF said that the brothers were known to police officials for their crimes in the past but nothing was related to terrorism [Brussels attack: Police identify attackers as Bakraoui brothers]

However on Thursday, Mar 24 Turkey President Recep Tayyip Erdogan said that one of the Bakraoui brothers was detained and deported in June last year. Khalid appears on the Interpol website and is sought for terror activities.

The federal prosecutor has said that Brahim blew himself up at the Brussels airport that killed 11 whereas Khalid was behind the Maelbeek Metro blast explosion where 20 people died.

Meanwhile a taxi driver came forward and said that he had picked the three suspects (Bakraoui brothers and another suspect) from an address in Brussels. Following this information, Belgian police raided that apartment and found explosives and other bomb making material.

Both the brothers were identified by DNA records.

Kouachi brothers and Charlie Hebdo attacks

Two brothers, Said and Cherif Kouachi struck the office of satirical magazine Charlie Hebdo on Jan 7 last year killing 11 people and injuring many. Both the brothers, accompanied by Amedy Coulibaly carried out two attacks, one at Charlie Hebdo and another at a Jewish hypermarket.

Following the atatck on Charlie Hebdo, both the brothers hijacked a car and were chased by police officials for a logntime before they finally took refuge in an signage production company in an industrial area in Dammartin-en-Goële.

Both the brothers remained in that building and that is when police were alerted about their presence. Following the tip off, a standoff began between the Kouachi brothers and police officials.

Despite repeated attempts by the officials to establish a dialogue, both the brothers were gunned down when they ran out of the building.

Tsarnaev brothers and Boston Marathon bombings

In April 2013, two pressure cooker bombs went off during the Boston Marathon. Two bombs were planted near the finish line of the marathon that killed three and injured more than 260 people. Soon FBI officials identified two Chechen brothers Tamerlan and Dzhokhar Tsarnaev who were behind the bombings and released their images.

The Tsarnaev brothers set off two homemade bombs containing fireworks, nails and metal shards at the event in a bid to be martyrs to the cause of jihad.

Once their images were made public, the brothers were on the run as they carjacked a SUV which then initiated a gunfight between them and police officials. During this Tamerlan was shot several times and was pronunced dead at the scene.

Meanwhile, his brother Dzokhar escaped only to be nabbed later. Dzokhar was found guilty in June last year and was sentenced to death. It was then that Dzokhar broke his silence and apologised for his actions.