CAIRO Human Rights Watch accused Egypt's ruling Muslim Brotherhood on Thursday of inciting religious hatred that led to the lynching of four Shi'ite Muslims in Cairo this week.
Residents of the suburb of Zawiyat Abu Musallem surrounded a house where a prominent Shi'ite cleric had arrived on Sunday for a religious festival. They attacked the guests, killing at least four and mutilating their bodies.
Police arrested eight people over the killings.
"The brutal sectarian lynching of four Shia comes after two years of hate speech against the minority religious group, which the Muslim Brotherhood condoned and at times participated in," said Joe Stork, deputy Middle East director at New York-based Human Rights Watch.
The Muslim Brotherhood, the movement of President Mohamed Mursi, was not available for comment.
Conservative Sunni Muslims, fearing the spread of Shia Islam in Egypt, have increased their anti-Shi'ite rhetoric since a visit by Iranian President Mahmoud Ahmadinejad in February, who called for a strategic alliance with Egypt.
Shi'ites, the majority in Iran, form a small minority of Egypt's 84 million population and keep a low profile.
"This horrific incident in Abu Musallem shows that Shi'ites can't even gather in the privacy of their homes to celebrate and heightens fear of persecution among all religious minorities in Egypt," Stork said.
President Mursi condemned the crime but his liberal opponents accuse him and his Muslim Brotherhood of allowing ultra-conservative Salafi allies to whip up anti-Shi'ite sentiment in return for their support.
Mursi was a guest of honor this month at a rally where a cleric described Shi'ites as heretics.
HRW's report said the investigation into the attack needed to look into the failure of police to intervene to halt the mob attack.
"The official response to the killings falls far short of what is needed to protect Shia in Egypt from future attack and protect their right to religious freedom," Human Rights Watch said.
(Reporting by Asma Alsharif; Editing by Alastair Macdonald and Robin Pomeroy)