Sergei Protazanov, a reporter for the Grazhdanskoye Soglasie newspaper, based in the north Moscow suburb of Khimki, died in hospital on Monday, two days after he was beaten near his home.
Police on Wednesday denied the reports of an attack on the journalist, saying his death occurred because of intoxication. They said Protazanov was found drunk near his home and hospitalized but released on Sunday.
A medical expert said he died as a result of poisoning by an unknown substance.
Lev Ponomaryov, leader of the For Human Rights movement and a member of the newly formed Solidarity opposition party, was attacked outside his east Moscow home on Tuesday.
"Ponomaryov, executive director of Russia's For Human Rights movement, was cruelly beaten by three unknown people at about 11:00 p.m. Moscow time [19:00 GMT]," the official's colleagues said.
Reporters Without Borders said on its website: "There seems to be no end to the appalling series of attacks on journalists, especially local journalists, and human rights activists. The authorities need to actively intervene instead of just issuing statements."
"Journalists and human rights activists must not only enjoy the same right to safety as other citizens but should receive special protection because of the particularly useful nature of their contribution to Russian society," the organization said.
Since the collapse of the Soviet Union in 1991, Russia has been one of the most dangerous countries for reporters. The most high-profile slaying was the 2006 death of Russian investigative journalist Anna Politkovskaya.
In January, Novaya Gazeta journalist Anastasia Baburova was shot dead alongside lawyer Stanislav Markelov in downtown Moscow.
Mikhail Beketov, editor-in-chief of the Khimki Pravda local newspaper, who fought a campaign to protect a forest near Moscow from destruction by developers, spent several weeks in coma after being badly beaten near his home in November.
