Last week Iranian Shiite cleric Ayatollah Safi Golpayegani said those who mocked Imams were committing apostasy – the rejection of religion which in Iran is a crime punishable by death, the Süddeutsche Zeitung newspaper reported on Monday evening.
The singer – who has been at loggerheads with Iranian authorities for years and has lived in exile Cologne since 2005 – last week released "Naqi," a provocative song in which he criticizes Iranian society and politics, news magazine Der Spiegel said on Friday.
This sparked an Iranian media campaign against Shahin Najafi, with newspapers saying his songs were proof of his apostasy, and calling for “appropriate consequences.”
Najafi told The Local in an email that calls were made for all Shiites and Muslims to find and kill him and “send him to hell.”
There was a storm of reaction online as death threats multiplied against the rapper, culminating in the anonymous offer of a $100,000 bounty on Najafi's head.
"I couldn't believe it," Najafi told German radio station Deutsche Welle radio on Friday.
"When I first saw the price on my head online, the $100,000, I really understood that it had got serious."
The threat intensified when a second Fatwa calling Najafi an apostate was issued by Iranian religious leader Ayatollah Nasser Makarem Shirazi via the Tabnak Iranian news agency, reported Focus on Tuesday.
The danger is that extremist Muslims in Germany or Europe take up the cause and try to kill him.
Najafi is now under police protection and has filed an official complaint against Safi Golpayegani, his manager told Deutsche Welle.
The rapper – famous for his lyrics critical of the Iranian authorities - has been living in exile in Cologne after being banned from performing in his home country. However, he says he did not intend to criticize Islam.
"I thought there would be some ramification," Najafi told the radio station.
"But I didn't think it would upset the regime that much. Now they are taking advantage of the situation and making it look like I was trying to criticize religion and put down believers.”
The musician has been forced to cancel some of his upcoming appearances. "He can't work now, he has to go to ground," said manager Schahryar Ahadi in the radio interview.
Najafi added that although he's afraid, he doesn't want to remain in hiding for long.
"I'm young and I'm an artist. I have to perform," he told Der Spiegel on Friday.