German prosecutors on Tuesday dropped a controversial investigation into German comedian Jan Böhmermann for reading a poem insulting Turkish President Recep Tayyip Erdogan, saying there was insufficient evidence to charge the comedian.

The Turkish government filed charges in April against the "Neo Magazin Royale" host after he read a lewd poem on the ZDFneo TV channel. The poem was a mixture of genuine criticism of Turkish policy - for instance towards Kurds - and lewd allegations about Erdogan personally, including saying he had sex with goats and engaged in sodomy. 

The poem led to a diplomatic spat between Berlin and Ankara.

German Chancellor Angela Merkel allowed authorities to launch an investigation into Böhmermann, citing paragraph 103 of Germany's penal code, an archaic law which protects foreign heads of state from insult.

In order for the investigation to move forward permission from the German government was required, prompting an outpouring of criticism on Merkel for restricting free speech  and kow-towing to Turkey.

Prosecutors in Mainz said in a statement on Tuesday that "criminal activity could not be proven with sufficient certainty." It also found that there was insufficient evidence to charge those involved in the production or broadcast of the poem.

The prosecutors' statement paraphrased Böhmermann's own defense of the show, broadcast in March. He had said that the song was a clearly an "exaggerated portrayal" of the Turkish president, and that "any listener should immediately recognize ... that it was a joke or a piece of nonsense." Böhmermann had cited the "lacking seriousness" and "the absence of a serious connection to the personal honor" of Erdogan within his poem.

"This stance is supported by the objectively verifiable circumstances, namely the content of the piece, its origins, and the manner of the delivery," prosecutors concluded. 

Böhmermann's poem was in response to Turkey summoning the German ambassador over a less lewd song criticizing Erdogan on another satirical show.

Ahead of delivering the poem, Böhmermann said that it was designed to demonstrate to Erdogan the difference between justifiable criticism and unsubstantiated insults that might test Germany's defamation laws.

Erdogan opened nearly 2,000 cases in Turkey against people who had allegedly insulted him before announcing an amnesty for cases within Turkey this July. 

The case led to a growing chorus of calls for the archaic law about insulting foreign heads of state to be abolished, a process now being explored in Germany's houses of parliament.

cw/msh (AFP, dpa, Reuters)