(CNN) -- The body of a journalist who was hacked to death in southeastern Nepal was cremated Tuesday as businesses and public transportation in the town of Janakpur remained shut for a second day to protest the killing.
Uma Singh, who was murdered in Nepal Sunday, had talked about the difficulties of practicing journalism.
Authorities said they arrested four people in connection with the death of Uma Singh, but they did not release the suspects' names or possible motive, said Damakant Jayashi, associate editor of the online news Web site, myrepublica.com.
"Journalists and human rights groups have descended on the town, and shops are shuttered in what almost seems like a spontaneous protest," Jayashi said.
"Journalists are all wearing black bands on their arms. And the FM stations in the city, all day yesterday, they played mourning tunes instead of their regular programs."
The killing of Singh, 26, is the latest in a "troubling trend" of attacks on reporters, the United Nations' human rights office in the country said. It asked the government to investigate the case and prosecute death threats against other journalists.
"Doing so will send a strong message that there will be no impunity for attacks against the media, nor for any serious crimes," the office of the U.N. High Commissioner for Human Rights in Nepal said.
Singh wrote for a daily newspaper and reported for a radio station in Janakpur, about 240 km (150 miles) southeast of the capital city, Kathmandu.
When she got home from work Sunday night, a group of about 15 men barged into the room she rented at a house and hacked her with "khukhuris" -- curved knives traditional to Nepal -- in full view of other boarders, authorities said.
"I am very very shocked," said Dharmendra Jha, president of the Federation of Nepalese Journalists, which is leading the protests. "If the government is not ready to provide any kind of security to journalists, it will be very difficult to do journalism in a free mode."
The group said it will announce a new phase of protests Wednesday.
Authorities do not have a motive for the killing. In some of her articles, Singh spoke out against the dowry system, where a bride's family is forced to give cash and property to the groom's family before the wedding.
Also Sunday, a group of men ransacked the house of another journalist in the same region, leaving a cross on her door and telling her it was her turn next, media groups said.
Police do not know if the two incidents are related.
In recent months, the number of attacks on journalists in Nepal have shot up. The federation released a year-end report, recording 284 incidents -- including three deaths and a kidnapping.
Some of the assailants have ties to the Communist Party of Nepal, the largest party in Nepal's coalition government, according to New York-based Human Rights Watch.
The party is led by Pushpa Kamal Dahal, or Prachanda -- a man who led a decade-long bloody insurgency before being sown in as prime minister.
During the decade-long civil war, Maoist forces under him carried out numerous attacks on journalists they believed were opposed to their cause, Human Rights Watch said.
And after he became prime minister, Prachanda issued a public warning to journalists while addressing a massive crowd in Kathmandu: "Now we will no longer tolerate criticism as we have already been elected by the people."
Three years ago, Singh's father and elder brother disappeared. Her family has all along accused local Maoist leaders of being behind the disappearances, Jayashi said.
Singh, herself, talked about the difficulties of practicing journalism in an interview with the United Nations last year.
"Various armed groups that are mushrooming have been a major challenge for us. We have been compelled to dance to their tunes. ...This makes us helpless," she said in the interview.
"What do we do? If we don't air the news of their choice, they threaten to kill us. Things have become very, very difficult for us."