CARACAS, Nov 28 (Reuters) - Venezuelan President Hugo Chavez said on Wednesday CNN may have been instigating his murder when the U.S. TV network showed a photograph of him with a label underneath that read “Who killed him?”

The caption appeared to be a production mistake -- confusing a Chavez news item with one on the death of a football star. The anchor said “take the image down” when he realized.

But Chavez called for a probe in an interview on state television, where he repeatedly reviewed a tape of the broadcast, questioning why the unconnected photograph and wording were left on screen for several seconds.

“I want the state prosecutor to look into bringing a suit against CNN for instigating murder in Venezuela,” he said. “... undoubtedly it is part of the psychological warfare.”

The anti-U.S. president often denounces plots to kill him without providing much detailed evidence. On Tuesday, he said a sniper trained his gun on him at a political rally this month.

Chavez has singled out CNN for biased reporting in what he says is a U.S.-sponsored campaign in the foreign media to destabilize Venezuela. CNN says its coverage is objective.

In power since 1999, Chavez on Sunday faces his tightest vote battle to date. Venezuelans will decide whether he can run for re-election indefinitely in a referendum that polls show is a dead heat between the “Yes” and “No” camps.

Well-known for wild accusations and harsh insults, Chavez usually focuses his attacks against the United States during campaigns. With the Bush administration avoiding being drawn into a spat, he has become involved in disputes with Spain and Colombia and repeatedly lambasted the Roman Catholic Church.

Some political analysts and Wall Street economists say the fights appear to be a tactic that burnishes his nationalist credentials and also helps distract voters from debating some of the unpopular details in his proposed reform package.