Chavez created the colectivos to bolster his support in working-class strongholds and Maduro unleashed them to take on the anti-government demonstrators who brought major cities to a standstill earlier this year.
But while they did much of the dirty work that helped him stay in office - many opposition leaders were hunted down and jailed - it is feared the process created a monster that Maduro can no longer control.
"The colectivos have become a force in their own right, they are all about power and money," said Marcos Tarre, a security consultant and political commentator.
"For a long time, the only things that united the disparate strands of the Chavismo movement were their greed for power and Hugo Chavez himself. Chavez created this chaos but he was also the only man who could control it. Maduro does not have the charisma or the capacity to hold this together any more."
The Government and the police have insisted there is no link between the killing of Serra and the raid on the Shield of the Revolution, one of whose leaders was a friend of his. Rather, they said that the colectivo had turned into a crime gang under investigation for several murders.
But others say the colectivos have simply become a challenge to the Government with their lucrative crime operations, intruding on the profits of state security forces that have often run similar illicit enterprises.
The fighting may also signify a proxy battle between Maduro and other factions within Chavismo, as the Venezuelan socialist movement in generally known.
Maduro, a former bus driver, does not share that view of how Serra came to an end. "Fascism decided to kill Robert Serra," he proclaimed, using the regime's usual description of Venezuela's right-wing opposition. "This is a terrorist escalation that they have been planning for a long time."
Such claims have a familiar ring to politics professor Hugo Perez Hernaiz, who has heard so many conspiracy theories from the regime that he collects them on a website. "Maduro is particularly adept at explaining almost every event in Venezuela as the result of a conspiracy by the Empire - the US Government - in cahoots with the local opposition," he said.
Chavez was a master at deploying coup and conspiracy accusations, aided by the fact that the US did back an attempt to overthrow him in 2002. A study by the Caracas-based newspaper Ultimas Noticias counted 63 supposed assassination plots between the time Chavez took office in 1999 and his death in 2013. But Maduro, his hand-picked successor, has taken the tactic to a new level as he accuses motley collections of his domestic foes - lumped together as "reactionaries" and "fascists" - with his international betes noires of America and Colombia.
The rhetoric does not stop at coup and assassination plots. When a mystery virus killed several patients in Caracas recently, the Government spoke of a "biological war" unleashed by dark forces seeking to defeat the revolution. The oil-rich nation's crippling economic problems are likewise said to be caused by an anti-socialist "economic war".
But no amount of rhetoric can hide the reality of life in Venezuela.
In the latest sign of the dire times, the Government has just begun a fingerprint registration scheme for shoppers to prevent hoarding of heavily subsidised basic goods, such as flour, rice and milk. Also on the list is toilet paper, recent shortages of which have spawned countless jokes about the state of the economy.
