Story highlights

Elena Milashina writes for Novaya Gazeta, an independent Moscow-based newspaper

She and a friend were beaten by unknown assailants early Thursday

Police have launched an investigation

Russia is one of the deadliest countries for journalists

CNN  — 

When Ella Asoyan first heard footsteps behind her and Elena Milashina, her friend and a prominent investigative journalist in Russia, she thought the young men might have just wanted to pass.

It was late, and dark. She turned to look at them – once, then once again.

“My gut feeling when I turned around the second time … was that he knew who she is,” said Asoyan, who spoke to CNN by phone.

She and Milashina were attacked by unknown assailants early Thursday on their way to Milashina’s home on the outskirts of Moscow.

Both were beaten. But Milashina, a reporter for Novaya Gazeta, an independent Moscow-based newspaper, bore the brunt of the violence, which stopped only after women walking by intervened.

In the wake of the assault, rights groups are calling for a full and impartial investigation.

Milashina frequently writes about human rights abuses and her stories may have made her a target, said the Committee to Protect Journalists (CPJ), a New-York based group that promotes press freedom.

Asoyan, who works for Freedom House, a democracy research and advocacy group, just happened to be in town that night with her friend.

“Russian authorities must investigate whether Elena Milashina was targeted because she investigated sensitive subjects, including human rights violations in the North Caucasus and the murder of her Novaya Gazeta colleagues,” said CPJ Program Coordinator Nina Ognianova. “Both Milashina’s work and the brutality of this attack point to the possibility that this was not a simple robbery. We call on authorities to do everything in their power to bring the perpetrators to justice.”

Human Rights Watch similarly demanded an investigation, both into the attack and the early police response to it.

Asoyan said she and Milashina waited at the scene for more than an hour after calling the police. Once police did show up, they initially treated the women with “absolute pejorative indifference,” Asoyan said. Their tune changed after the case started to attract attention, she said.

Asoyan added that police have since launched a criminal case.

The attack left Milashina with a concussion, extensive bruising and a broken tooth, according to the CPJ. Asoyan also suffered bruising.

The assailants took Asoyan’s laptop and money from Milashina, though Asoyan doubts the attack was a robbery. At one point, one of the men grabbed her purse. She was able to get it back and he made no further attempt to get it, she said.

“The logical thing for a thief to do is to run with it. He stayed there,” Asoyan said. “For a random act of violence, this was a little too bizarre.”

The attack will likely heighten concerns in Russia, one of the deadliest countries for journalists.

In one of the highest-profile killings there, Anna Politkovskaya was found shot dead in her apartment building in 2006. Like Milashina, she worked on sensitive stories for the Novaya Gazeta newspaper. Politkovskaya was a fierce critic of the Kremlin.

Despite the initial police reaction, Asoyan said, she is hopeful authorities will solve the case and bring her assailants to justice.

“Frankly, I think it is very important for the Russian police to take this case seriously. If this case can be solved … it might change the culture and the system of police response and police responsibilities,” she said.

CNN’s Dana Ford contributed to this report.