The editor-in-chief of an Azeri opposition magazine has been killed in front of his home in Baku.
Huseynov was fiercely critical of the authorities
Elmar Huseynov was reportedly shot seven times while walking out of the lift at about 1700 GMT, news agency Turan reported.
The magazine, Monitor, is strongly critical of Azeri authorities and President Ilham Aliyev.
Huseynov had been sued for defamation after accusing local officials of behaving like the Sicilian Mafia.
Human rights groups have already linked the murder to his journalistic activities.
"Huseynov became the victim of his citizen's activism - this is terrorism against the press," said Arzu Abdullayeva, a representative of the international Helsinki human rights committee in Azerbaijan.
An employee with the magazine, who witnessed the murder, has alleged that Huseynov might have been the victim of a contract killing.
"When Huseynov was leaving a lift in his apartment block the lights went off," the man, who asked to remain anonymous, told Reuters news agency.
"Then I heard several pistol shots, and when the light was back, Huseynov was dead."
Only two days ago, two opposition journalists said they had been detained and beaten up by the police.
But analysts here say this murder is by far the most serious case in a long list of assaults on journalists in Azerbaijan.
Most opposition and independent newspapers in Azerbaijan condemned the murder.
The opposition newspaper Yeni Musavat dubbed Huseynov "the first martyr of the free press" on its front page.
The chairman of the People's Front of Azerbaijan Party, MP Ali Karimli, told the paper: "This is an act of state terror.
"At the very least the nation should rise against this."
The leader of the opposition Musavat Party, Isa Qambar, told the paper that the government was conducting a campaign of "terror against freedom of the press, independent and brave journalists, free-minded people and the nation itself".
The Xalq Cabhasi newspaper, mouthpiece of the pro-government United People's Front of Azerbaijan Party, blamed the murder on "forces both at home and abroad who are ready to lead to confrontation and upset stability".
The independent daily Ekspress said "the chief of the Baku City Main Police Department does not rule out that the journalist's murder was an act of sabotage against the state".
Mr Aliyev succeeded his father as president in 2003.
The elections were criticised by international observers, and were followed by violent protests.
Several opposition leaders were jailed in connection with the riots.