A world-renown Muslim human rights lawyer says he's been the target of a slew of death threats after he dared last week to call for Muslims to unite against Islamic extremism.

Scottish police said they were investigating the threats against attorney Aamer Anwar, who claims "fanatics" are targeting him, The Telegraph reports. Anwar reportedly urged Scotland to keep hate speech from entering his country "from the cesspit of extremism in Pakistan."

Anwar had called for religious unity after police said a 32-year-old Muslim man in Glasgow stabbed a Muslim shopkeeper in late-March, killing him. The shopkeeper, 40-year-old Asad Shah, had apparently posted messages on Facebook calling for religious harmony: "Good Friday and very happy Easter, especially to my beloved Christian nation x!"

After the killing, Anwar invited speakers from different Muslim sects to condemn the violence, The Telegraph adds. He said that he felt alone in the fight against Islamic extremism, but he refused to stay quiet.

“It is a terrifying and deeply lonely place to be when you say goodbye to your children and wonder if it is for the last time, but the death of Asad Shah should be a wake up call to our community that we must not be silenced," Anwar said.