Conspiracy theories are usually the territory of internet message boards and guys wearing tinfoil hats. But now, acting Venezuelan President Nicolas Maduro has stepped into that prestigious company by launching a formal inquiry into whether Hugo Chavez's cancer was the result of poisoning by a foreign government.

"We have the intuition that our commander Chavez was poisoned by dark forces that wanted him out of the way," Maduro said, according to Reuters. Critics dismiss such claims as Maduro's way of keeping the focus on "imperialist" oppressors instead of his own government's failings. Either way, there are plenty of shadowy theories to go around. Let's take a quick tour through the fringes...

1. Hugo Chavez was poisoned
The rumor that Chavez's tumor was the result of a foreign plot has been around since he was first admitted to the hospital in 2011. After Chavez's death, Maduro ramped up the rhetoric, blaming the late president's demise on Venezuela's "historic enemies," i.e. the United States.

Uncle Sam is having none of it. "We completely reject the Venezuelan government's claim that the United States is involved in any type of conspiracy to destabilize the Venezuelan government," said State Department spokesman Patrick Ventrell, according to The Wall Street Journal. That didn't stop Maduro from expelling two U.S. diplomats from the country shortly after assuming power.

This particular conspiracy theory has at least one prominent believer outside of Venezuela. Bolivian President Evo Morales has said that he is "almost certain" that Chavez was murdered, warning that the "Empire has all the instruments to plan actions to overthrow governments, leaders, social movements that are against capitalism," according to the Buenos Aires Herald.

One problem with the idea of assassination: Most scientists believe it's impossible.

2. Chavez actually died a long time ago
In February, a questionable report surfaced from CNN Chile's 11 a la Hora that Chavez had been dead since late December — even as Venezuela claimed that he was recovering in a Caracas hospital. The source of this report was Guillermo Cochez, formerly Panama's ambassador to the Organization of American States, who, according to Quartz, claimed that photos of Chavez smiling with his daughters were fake. Why the Venezuelan government would pull a Weekend at Bernie's is beyond us... and plenty of Western media observers are skeptical.

3. And he actually died in Cuba
This theory, as reported by The Telegraph, was first circulated by Spanish newspaper ABC. It says that Chavez was transferred to Cuba after receiving treatment in Caracas, where he eventually passed away. Then, apparently, he was flown back to Venezuela so that the government could announce his death. How did they pull this off?

It was suggested vice-president Nicolas Maduro was engaged in distraction techniques to attract the media's attention with the announcement that two US embassy officials were expelled while Chavez's body was returned. [The Telegraph]

The "old expel diplomats while your dead leader is returned" routine. Classic.