A word in your ear: Bert stars in the corner of this poster
The yellow Muppet was seen at Bin Laden's shoulder on placards carried by demonstrators on the streets of Dhaka this week.
The makers of Sesame Street are angered by the association, saying in a statement that it was "outraged" by the teaming of the apparently benign children's TV character with the prime suspect of the 11 September attacks on the United States.
The images apparently originate from a number of web sites called Bert is Evil, which argue that Bert is actually a dark genius who is connected to several high-profile personalities.
Mostafa Kamal, the production manager at Azad Products, the Dhaka shop which made the posters, told AP news agency that he had got the pictures from the internet.
He said they had not noticed anything unusual about them at the time, and would not be using the pictures in the future.
The company sold about 2,000 posters to demonstrators angry about the US military strikes on Afghanistan.
Legal action
But Sesame Workshop, which produces the show, said it was considering all legal avenues to prevent the misappropriation of Bert in the future.
"Sesame Street has always stood for mutual respect and
understanding," the company said. "We're outraged that our characters would be used in this unfortunate and distasteful manner."
Bert - whose day job is playing the grumpy sidekick to fellow Muppet Ernie in the children's TV show - is seen in several posters, one of which shows him clutching a bottle of what looks like whisky.
The creator of the original Bert is Evil site, the Californian-based artist Dino Ignacio, said he had nothing to do with the images.
"Reality is imitating the Web!," he said in a statement. "I am honestly freaked out!"
However, he later took down the site, saying: "I am doing this because I feel this has gotten too close to reality and I choose to be responsible enough to stop it right here."