The capture of Diego Montoya by an elite army squad this week is Colombia's biggest break against the cartels since Pablo Escobar was tracked down and shot to death in 1993. But just as Montoya learned from the demise of Escobar's Medellin cartel, his successors in the Norte del Valle cartel will likely be smaller outfits.

The drug trade has become increasingly compartmentalized - the era of vertically run cartels that controlled everything from the coca plant to U.S.-bound planes and speedboats ended a decade ago - and authorities doubt any would-be cartel leader can maintain the 250-strong private army and intelligence network that helped Montoya evade capture for so long.

Now jailed awaiting extradition on a 1999 warrant filed in Miami, Montoya was transferred to a Colombian navy frigate in the Pacific for added security on Friday. Meanwhile, soldiers and police flooded into the cartel's Cauca valley stronghold, anticipating an internal war between cartel figures.

Montoya started out as a cocaine-processing "chef," and rose to become a leader of the cartel through violent acts that allegedly included the murders of 1,500 people. Now experts are betting the vacuum will be filled by Montoya's longtime rival, Wilber Varela. A former policeman, he, too, rose swiftly through the ranks, after beginning as a chauffeur.

Like Montoya, Varela has a $5 million U.S. reward out for him, and faces extradition if arrested on charges he helped export more than 500 tons of cocaine.

Battles for the allegiance of top lieutenants swiftly follow a drug lord's capture in Colombia's underworld.

"What happens is that when one capo falls, the others grab his people," said Alfredo Montenegro, Colombia's chief anti-narcotics prosecutor.

And so it was just a day after the arrest last month of Juan Carlos Ramirez, who allegedly ran money laundering operations from Brazil. Varela telephoned Ramirez' top enforcer and said "'You're working for me now,'" said Montenegro, citing police intelligence. "The guy knew that if he didn't agree to work for Varela he'd be dead."

Varela, 49, fought Montoya in a four-year turf war that left more than a thousand people dead. Varela also has a private army that may give him the upper hand against three top Montoya subordinates, authorities say.

The likeliest of these to emerge on top is Omar Varela (thought to be no relation to Wilber), otherwise known as "Capachivo," according to Col. Cesar Pinzon, chief of Colombia's judicial police.

Omar Varela was indicted in Florida in February on charges of trafficking cocaine for 20 years and being involved in the torture and killing of an informant. Colombian police believe he may have masterminded the massacre of 10 elite Colombian anti-drug agents in 2006, a slaughter for which a number of soldiers are on trial.

But any eventual winner could be running a much smaller operation in the cartel, which has been weakened in recent years and now relies on leftist rebels and right-wing paramilitaries for much of its cocaine.

One reason is that these would-be successors, while powerful, were kept away from the Montoya organization's money, said Pinzon, whose force spearheads Colombia's anti-narcotics efforts.