Viktoria Marinova is the third reporter to be killed in Europe in the past year. (Reuters)

Highlights Viktoria Marinova was anchoring a show focused on investigative reporting

She is the third reporter to be killed in Europe in the past year

The motive behind her killing remains unknown

Viktoria Marinova, a 30-year-old Bulgarian journalist who had recently become the anchor of a talk show focused on investigative reporting, was raped and killed on Saturday in a case that has sent shockwaves through Europe.

The motivation behind her killing remains unknown, and Bulgarian authorities say they have yet to establish a link between her death in the northeastern city of Ruse and her work as a journalist. But because Marinova is the third reporter to be killed in Europe in the past year, the news stoked anxieties about the safety of journalists on the continent.

"Again a courageous journalist falls in the fight for truth and against corruption," Frans Timmermans, vice president of the European Commission, said Monday in Brussels. The European Union pledged its support for Bulgarian authorities as they continued their investigation.

Bulgarian officials emphasized that there was no evidence yet to connect Marinova's killing to her work.

"It's about rape and murder," Interior Minister Mladen Marinov said.

Bulgarian media reported Monday that the park where Marinova was killed is adjacent to a psychiatric facility and authorities were investigating whether a patient could have been Marinova's attacker.

"The best criminologists have been sent to Ruse - let's not hurry them," Bulgarian Prime Minister Boyko Borissov said. "A large amount of DNA has been obtained."

Marionva, a former lifestyle journalist, was a television presenter for TVN, a popular channel in northeastern Bulgaria. Last month she began anchoring a program called "Detector," which focused on political investigations.

Only one segment of the relaunched program aired before her death. It featured the work of two journalists investigating the alleged misuse of public EU funds by a network of corporations in the region. The journalists - Dimitar Stoyanov, from the Bulgarian website Bivol, and Atilla Biro, a Romanian journalist from the Rise Project - were briefly detained by local authorities in mid-September.

Transparency International, a global corruption watchdog, has identified Bulgaria as the most corrupt member state in the EU. Meantime, Reporters Without Borders ranked it 111 out of 180 countries in its annual world press freedom index, the lowest in the European Union.

Atanas Tchobanov, the editor-in-chief of Bivol, said in a telephone interview that he was skeptical of the government's response. "We cannot downplay any possibility and any version, but if you are investigating the killing, you are looking for a motive," he said.

At the same time, he clarified that Marinova was a television presenter and technically not an investigative reporter. "She wanted to make investigative reporting," he said. "Who knows? Probably she would be a good investigative reporter one day, but she's no longer here."

Marinova's killing - as a random act of violence or as a targeted hit - comes after two other cases that provoked concerns about press freedom in Europe.

In October 2017, Daphne Caruana Galizia, a Maltese reporter who specialized in government corruption and money laundering, was killed by a car bomb near her home. And in February, Jan Kuciak, a Slovakian journalist who also reported on government corruption, was shot and killed along with his financee, Martina Kusnirova.

Also on the minds of press freedom advocates is the disappearance of Jamal Khashoggi, a prominent Saudi critic and Washington Post contributor, who vanished last week after entering the Saudi consulate in Istanbul. Turkish authorities have asserted that he was killed upon entry.