Ever since the crackdown on the Syrian uprising began last year, opposition supporters have maintained that the real power is in the hands of Maher al-Assad, Syrian President Bashar al-Assad’s dreaded younger brother.

As the commander of the Syrian Army’s elite Fourth Armoured Division and Republican Guard, Maher - “the enforcer” of the government’s brutal military assault - was personally responsible for crushing protests in the southern Syrian city of Deraa, earning himself the nickname “the butcher of Deraa”.

On Feb. 29, when an unnamed Syrian official told the Associated Press that the Baba Amr district of Homs would be “cleansed” within hours, Syrians inside and outside their homeland had no doubt that the feared Fourth Division would be conducting the “cleansing” operation.

In an interview with FRANCE 24, Hamza al-Omar, a member of the opposition Syrian Revolution General Commission, said reinforcements from the Fourth Division had arrived in Homs.

"We were able to identify from the distinctive signs visible on the armour and we have elements within the army who informed us in advance of the arrival of these reinforcements," said al-Omar.

Another opposition activist, Mohammad al-Homsi, also told FRANCE 24 that the reinforcements at Homs belonged to this elite squad.

Controlling army desertions

Comprised mostly of Alawites, the sect to which the Syrian president and his brother belong, the Fourth Division’s loyalty can relied upon at a time when the regime is seeing massive desertions to rebel for - particularly among the conscripts and lower ranks, which are predominantly held by the country’s majority Sunni Muslims.

US Ambassador Robert Ford speaks to FRANCE 24

"The Fourth Division is known for its brutality and it’s a symbol of the regime’s striking force,” said Khattar Abou Diab, a political scientist at Paris-XI University.

According to Akil Hachem, a former brigadier general in the Syrian Army currently in exile in France, the Fourth Division is also well equipped and its members well-trained. “This squad of killers is very experienced and highly trained. They are commanded by career officers and have the best weapons available in Syria.”

At the start of the opposition demonstrations, the Fourth Division was dispatched to quell the uprisings in successive towns and cities across Syria. “Unable to deploy on all fronts, it has been divided into several sections to supervise and direct the various law enforcement operations,” said Hachem.

Another reason for the unit’s deployment seems to be the fear it inspires among Syrian military ranks. “The other Syrian soldiers are wary and afraid of these elements, because they are well aware of the unit’s track record and the massacres they committed in the past in Syria and Lebanon,” said Hachem. “This fear prevents the defections of soldiers who know they are under surveillance.”

Like father, like son: A younger brother to the rescue

In Syria, the past sometimes has an uncanny - if cruel - way of repeating itself.

The current Syrian Fourth Armoured Division is a merger of the old Defense Companies, a paramilitary force that was led by Rifaat al-Assad, the younger brother of former Syrian strongman Hafez al-Assad.

Rifaat al-Assad is perhaps best-known for his role in personally overseeing the notorious 1982 Hama massacre, in which at least 10,000 people were killed.

A number of experts have noted that during Hafez al-Assad's presidency, Rifaat functioned as his brother's enforcer in much the same way as Maher now plays the role of heavy to his elder brother, the current Syrian president.

In an interview with the New York Times last year, Bassam Bitar, a former Syrian diplomat who now lives in exile in the US, said, “If you look back at the uprising from ’79 to ’82, Rifaat was the nasty guy, the killer. And now history repeats itself, and Maher is a nasty guy.”

All in the family

Hafez al-Assad's youngest child, Maher, pursued a military career like his eldest brother, Basil - whom many believed had been pegged to succeed his father - until Basil died in a 1994 car crash.

A 1985 Assad family photograph shows in the front, former Syrian president, Hafez al-Assad, and his wife, Anisa. The children in the back row, from left to right, are Maher, current Syrian President Bashar al-Assad, Basil, Majid, and Bushra.

Shortly after Basil’s death, there was some talk that Maher could be a possible successor. But many experts and ordinary Syrians disagreed: the youngest al-Assad son had a reputation as a hot-tempered, impetuous young man.

Maher is widely rumored to have shot his brother-in-law, Gen. Assef Shawkat, during an altercation. Shawkat survived and the two are believed to have patched up their differences. He currently serves as Syria’s deputy Minister of Defense.

Like his father and many other Arab dictators, Bashar al-Assad has relied on his family to consolidate and maintain power.

Just as his uncle did the bloody work for his father, Maher has taken on the brutal business of keeping his beleaguered elder brother in power.

By Thursday, Baba Amr, a district of Homs that turned into a symbolic rebel holdout, had passed into government control following what opposition fighters called a “tactical withdrawal”.

Confronted with a deadly, sustained 27-day bombardment, the opposition fighters found themselves outgunned and outmatched. The enforcer, it seemed, had won the latest round.