Five armed men held a Sri Lankan newspaper editor at knifepoint as they searched her home on Saturday before police burst in and shot one of the intruders dead, officials said.
The attack was the latest in a string of violent incidents involving the staff of the Sunday Leader and media activists said they suspected the incident at the Colombo home of Associate Editor Mandana Ismail Abeywickrema was an attempt to intimidate her.
Police spokesman Buddhika Siriwardena said three officers were injured when the intruders attacked them with knives. "One intruder was shot dead and the other four have been arrested," he said.
Police described the pre-dawn intrusion as an attempted armed robbery but the island's main press freedom organisation, the Free Media Movement (FMM), said they suspected the attack was linked to her work.
Abeywickrema has been critical of the government in her political commentary and recently set up a trade union for journalists.
"The intruders spent a lot of time inside the house going through files and documents," FMM convenor Sunil Jayasekera told AFP.
"If they wanted only the valuables, they could have taken them and got out much earlier. But they were clearly looking for something else."
In 2009, the Sunday Leader's editor, Lasantha Wickrematunge, was shot dead near his office just outside the capital. He had been a fierce government critic.
Six months ago, gunmen shot and wounded another of the paper's journalists at his home near Colombo.
The investigative newspaper was considered anti-government until last year, when it was bought by a businessman who is widely seen to favour President Mahinda Rajapakse's administration.
In September, the newspaper's new owner dismissed the editor, Frederica Jansz, who said she was fired after resisting demands to water down criticism of the president.
She has since fled to Canada saying she received death threats.
The latest incident came a day ahead of a fact-finding mission to the island by the UN's human rights chief Navi Pillay.
Media rights groups have said Sri Lanka remains a dangerous place for journalists despite the end of a decades-long war between the military and Tamil separatist rebels in 2009 and that attacks against journalists and news outlets have continued.
Sri Lanka lifted a state of emergency in 2011, but media activists say journalists have been forced to self-censor their work due to fear of attacks.