The recent deaths of four journalists in four countries over four days illustrates not only the continuing danger that journalists face across the globe, but the need to protect their safety and fundamental rights and end impunity for crimes against them, the International Press Institute (IPI) said today.

Journalists died in Brazil and Ukraine, respectively, on Friday and Saturday, and two more were killed on Monday in Uzbekistan and Colombia. Three of the four were violently murdered, with no clear evidence for why they were attacked or whether those responsible will be charged for their deaths.

The deaths followed a fifth last Thursday, when unidentified men wielding machetes in Bangladesh’s capital Dhaka hacked blogger Avijit Roy to death.

On Friday, Brazilian radio and TV host Ivanildo Viana, 51, was murdered while riding his motorcycle on a highway between Santa Rita and João Pessoa in the state of Paraiba, the Committee to Protect Journalists (CPJ) reported. Local reports indicated that two, possibly three, men shot Viana three times in the back and once in the head, leaving his body on the side of the highway.

Police have not released any leads on the case nor have they apprehended any suspects. Viana worked for 100.5 FM Lider for 20 years and hosted the daily show “100% You”. According to friends, he had not reported any previous threats or harassment, and it remains unclear if his murder came in response to his professional work.

Frei Anastacio, a member of Paraiba’s Legislative Assembly, called on Tuesday for the Assembly to provide a plan of action to combat the violence against media professionals. Anastacio cited Viana’s murder, a recent attack on blogger Mario Luiz and the December 2014 attack on radio broadcasters Lindemberg Tavares and Wesley Silva.

In eastern Ukraine, photojournalist Serhiy Nikolayev was killed on Saturday in an artillery attack near the village of Pesky, northwest of Donetsk. Despite a ceasefire ordered two weeks ago, shelling continued along the Ukrainian frontline. Nikolayev was a staff photographer for Segodnya newspaper though the newspaper’s editor claims the he was not in the area on assignment.  According to IPI’s Death Watch, Nikolayev was one of seven “journalists or media workers” killed amid conflict in the east since last year.

On Monday, the body of a popular Uzbek TV anchor, Rakhmatilla Mirzaiev, was found with numerous stab wounds in the backyard of his house in the Zangiota district in Tashkent province. Mirzaiev had worked for Uzbek state TV for four decades.

The initial report of the anchor’s death came via Facebook from his colleague, Muslimbek Yuldashev, and was not initially confirmed by authorities.  The Interior Ministry announced yesterday that a 21-year-old suspect had been arrested, but there has been no indication of what motivated the murder nor were further details about the suspect disclosed.

Also on Monday, Colombian radio journalist Edgar Quintero, 57, was shot seven times in a local bakery in Palmira. Quintero worked for Radio Luna for 20 years and was the director of the program “Noticias y algo más” (News and More).

Police announced yesterday that they had no leads as to the culprit responsible for Quintero’s death or why he was attacked. It was not known whether he had been previously threatened.

He was the second journalist killed within a month in Colombia, after radio station owner Luis Peralta, who was shot and killed on Feb. 14. The motives behind Peralta’s murder also remain unclear, though authorities said they had captured the suspected killer on Tuesday.

IPI Director of Advocacy and Communications Steven M. Ellis said the spate of recent deaths illustrated the danger facing many journalists.

“The number of journalists’ deaths so soon in 2015 shows that journalists are reporting in increasingly hostile environments, whether in conflict zones or not,” he said. “These journalists and their families deserve justice, and one of the most important steps in ensuring that such crimes aren’t repeated is for authorities to show those who would attack journalists that they will be punished.”