AS befitted the violent, secretive world of Mexico's illegal drug cartels, he was known as The Executioner and Z-3.

A one-time elite special forces soldier, Heriberto Lazcano switched sides to join the very gangsters he was charged to fight. In the process, Lazcano rose to become the kingpin of Mexico's biggest and most brutal narcotic trafficking mob – Los Zetas.

All this, of course, was before Mexican marines caught up with him this week in the town of Progreso, where Lazcano and his bodyguard were gunned down in a firefight.

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Lazcano was only the latest casualty among a staggering 60,000 people killed over the past six years in a gruesome and macabre drug war. In this warzone, brutality knows no bounds.

Indeed, it's not uncommon for victims of the cartels' hitmen to be slowly burned alive in 55-gallon drums of flaming diesel, have their severed heads rolled on to crowded nightclub dance floors or their faces sliced off and stitched to footballs before being dumped with an attached warning note to rival gang members.

However, even by these outlandish standards, what happened in the wake of Lazcano's death was weird.

His corpse was delivered to a funeral parlour in Sabinas, Coahuila state. Hours later, masked armed men arrived and stole the body.

The Mexican Navy, which conducted the operation against the Zetas leader, was quick to insist that fingerprints and photographs had been used to formally identify the body as Lazcano's before it was stolen.

Others, though, are less convinced. To begin with, there is the question of why the Navy allowed local authorities to conduct preliminary forensic verification tests but subsequently did nothing to guard the body of what it believed was a high value target.

After all, proof of Lazcano's death carried with it considerable political capital for Mexico's President Felipe Calderon and his "kingpin strategy" to undermine drug cartels by wiping out the top bosses.

How curious it is too that Mr Calderon, though willing to confirm that the man killed was the Zetas leader, has so far studiously avoided mentioning the theft of the body.

Perhaps Mr Calderon is embarrassed by the discrepancies in reports of the death.

The most obvious are those raised by US Department of Justice officials who say Lazcano's "biometrics" do not match those of the dead man taken to the funeral parlour in Sabinas.

According to US reports, Lazcano was 5ft 8in tall, whereas the Mexican Navy said the body of the man they killed was 5ft 2in.

While it might seem like a minor detail, such things matter in a drug war where conspiracy is a powerful motivator and virtually a way of life. Perhaps it's worth remembering Lazcano had previously been reported killed in a June 2011 shootout in Matamoros.

Given such a climate, it's doubtful the speculation surrounding Lazcano's real fate will dissipate any time soon.

Perhaps even more important is the impact Lazacano's death/disappearance from the scene might have on Los Zetas internal structure and its implications for other rival cartels and the illegal Mexican drug trade as a whole.

Some analysts say a power struggle inside the Zetas is almost inevitable with Lazcano gone.

Certain media reports over the past several months have concentrated on claims that Lazcano and Los Zetas number two Miguel Angel "Z-40" Trevino Morales had become rivals.

But there are some within the international drug enforcement community and other intelligence analysts who insist there is little evidence to support this.

Instead, these sources point to the fact Lazcano had reportedly been suffering from a terminal illness for some time and had simply transferred leadership of Los Zetas to Trevino in an orderly manner several months ago.

If the leadership transition of Los Zetas has taken place in this way few doubt that Trevino is more then capable of handling the group's operations as competently as his predecessor Lazcano.

That said, Trevino does face other internal challenges, notably a Zetas schism in the regions of Zacatecas, San Luis Potosi, Coahuila, and Nuevo Leon, led by Ivan "El Taliban" Velazquez Caballero, a regional Los Zetas boss who is challenging Trevino's authority in those territories.

Taking its name from the radio code Z used by high-ranking officers in the Federal Judicial Police who were nicknamed as the letter in Spanish, the Zetas cartel was formed in 1998 by 14 former soldiers of Mexico's elite Grupo Aeromóvil de Fuerzas Especiales – the Special Forces Airmobile Group.

Of all the clues as to how Los Zetas will cope with any fresh leadership restructuring, this military pedigree provides the best indicator. Because ex-military personnel formed Los Zetas, members tend to move up in the group's hierarchy through merit rather than through familial connections, and members are groomed to step into leadership when the need arises.

This contrasts starkly with the culture of other gangs, including Mexico's other big cartel player the Sinaloa Federation led by Joaquin "Shorty" Guzman, another of Mexico's most wanted men.

If in the coming months it becomes clear Trevino moves to poll position as boss of Los Zetas it's certain he will run it with an iron fist.

Difficult as it is to believe, Trevino is generally considered even more ruthless and brutal than the elusive and seemingly now fallen capo, Lazcano.

Yes, even if we are talking about a man whose idea of retribution was to have his enemies – or their children – submerged in cauldrons of boiling oil.

At Trevino's disposal comes a Zetas command of more than 10,000 gunmen from the Rio Grande, on the border with Texas, to deep into Central America.

According to the US authorities, the Zetas now control the lion's share of an illicit trade in cocaine, methamphetamine and heroin thought to be worth between £11 billion and £25bn annually in North America alone.

It is a measure of the threat Trevino and the Zetas pose that the US State Department has offered a reward of up to $5 mil-lion (£3m) for information leading to his capture.

However, as the recent mystery and debacle surrounding the demise of Lazcano has shown, that could be a long time coming.

For now Trevino will most likely prove as elusive as his predecessor and business will prove as profitable as ever.