Another secular writer has been murdered in a hacking attack in Bangladesh.

Nazimuddin Samad, a law student, was walking home in Dhaka Wednesday when four masked men on a motorcycle yelling "Allahu Akhbar" started hacking him with machetes. As he fell, one of the attackers shot him.

"It is a case of targeted killing," said deputy commissioner of Dhaka Metropolitan police Syed Nurul Islam.

While police say they have no suspects, the killing fits the pattern of those killed before him.

Samad, 28, joins five other Bangladeshi secular writers and publishers murdered by the Islamists they opposed, including American Avijit Roy. He was included in "hit lists" targeting atheist writers.

Samad was part of a secular activist group called Ganajagran Manch, and his writings often criticized Islamists. "Evolution is a scientific truth," he wrote on Facebook. "Religion and race are invention of the savage and uncivil people."

In an apparent effort to prove they were not savage and uncivil, radical Islamists set upon Samad with machetes.

"He didn't kill anyone. To me he's a good person. He didn't do anything wrong," Mustakur Rahman, a friend, told The Guardian. "He wrote something about a particular religion. I'm a believer, but he wasn't a believer and maybe he was trying to express what he thinks about religion. It is a free world, why should he be killed?"

Samad's murder on a Dhaka street "is a grave reminder that the authorities are failing to protect people exercising their right to freedom of expression," Amnesty International said in a statement.

Bangladeshi officials have not adequately condemned the ongoing slaughter, the statement said, noting they have instead acted to curb actions and statements which might "gravely hurt religious sentiments."

"There can be no justification for the brutal killing of Nazimuddin Samad, who has apparently paid with his life for nothing but being brave enough to speak his mind," said Amnesty International South Asia Director Champa Patel. "This is not just a senseless murder, it is a blatant attack on the right to freedom of expression."