Devotion, glow, faith and kindness. These were among the English words that Viktoria Marinova had jotted down on notepaper that lay untouched on her desk at the TVN studios in Ruse three days after her body was found in parkland beside the river Danube.

The words seemed appropriate, given that all those who knew Marinova spoke of her warmth, determination and devotion to social justice. The 30-year-old journalist disappeared after going for a run by the river on Saturday and her body was found later that day. Bulgarian police confirmed she had been raped before she was killed.

It was the third murder of a journalist in an EU country within a year, reopening debates about the dangers of reporting, as well as the particular perils faced by female journalists. Last October, Daphne Caruana Galizia, a Maltese investigative journalist, was killed when a bomb planted in her car detonated. In February, Ján Kuciak, a Slovak journalist, was shot dead along with his girlfriend.

Nobody in Ruse, Bulgaria’s fifth largest city, expected that the next killing would be here. The attack has divided Bulgaria’s journalistic community, with some viewing it as a dark omen about press freedom in the country and others saying it was a tragedy but unlikely to have been linked to her writing.

Authorities have said they are investigating all possibilities but say they are cautious about linking the murder to Marinova’s journalism. On Tuesday afternoon, the police announced that a Romanian citizen had been detained, but later said there was no apparent connection with the case and he would be released.

Later, Bulgarian media reported that a man had been arrested in Germany and said statements from high-level officials were expected on Wednesday. There was no immediate confirmation.

Marinova worked for TVN, a small regional channel based in Ruse. Her new show was called Detektor. The first episode, which also turned out to be the last, featured interviews with two investigative journalists working on a corruption investigation into misuse of EU funds, led by the Bulgarian investigative outlet Bivol.

During the broadcast, Marinova lamented the state of media freedom in Bulgaria and promised her show would continue to discuss corruption scandals and carry out its own investigations. Transparency International ranked Bulgaria 111th out of 180 countries in its most recent press freedom index, the lowest of any EU country.

“Viktoria Marinova was not a professional investigator but she dared to speak about this and give others the possibility to discuss it,” said Atanas Chobanov of Bivol. He condemned Bulgarian authorities for immediately dismissing the possibility of a contract killing and claimed police had not even studied CCTV footage from around Marinova’s workplace to see whether she was being followed.

He said Bivol journalists had received “credible threats” related to their investigation in recent weeks and passed them on to police.

However, some of Marinova’s own colleagues were not convinced the killing was related to her work. Ivan Stefanov, the channel’s chief producer, who worked with Marinova on Detektor, said she was not working directly on any investigative reports. He said she had not reported any threats before the attack, nor had she spoken of noticing anyone following her or of having any personal problems.

Among those mourning Marinova were a group of activists attempting to change legislation to improve rights for disabled children and their families. She had devoted much attention to the issue in recent months in her reports and through charitable work.

“Viktoria gave people a voice. I can say only good things about her. I am grateful to her for her support,” said 44-year-old Nadezhda Dimova. “She inspired me not only as a journalist, but as a human being. People are dying because this legislation has not been changed.”

On Tuesday evening, more than 100 joggers, some of them carrying flowers, gathered by the Danube in Ruse to run 5km to the spot where Marinova’s body was found. Its organiser Velizar Tashev read out a list of demands, including for authorities to install CCTV cameras along the embankment and improve police patrols.

The killing fits into a pattern of violent attacks on female reporters. Last October, a Russian radio journalist, Tatyana Felgenhauer, was stabbed in the neck at her station’s Moscow studio by a 48-year-old male intruder who had monitored her broadcasts and written blogposts about her. Last August, the Swedish journalist Kim Wall was sexually assaulted, murdered and dismembered by a Danish inventor, Peter Madsen, while onboard his miniature submarine. Madsen was jailed for life for the attack.

“The fact that a woman has been killed in such a brutal manner – which is, by the way, happening on a daily basis – is what matters,” said Ivan Enchev, an IT specialist who attended a vigil for Marinova in Sofia on Monday evening. “It doesn’t matter whether it was a punitive action for her work or an attack against a woman, there is no positive aspect to this story. I want to express my disgust with the horror we live in.”

The sentiment was echoed by Irina Nedeva, a radio journalist and head of the Bulgarian office of the Association of European Journalists. “This is a nightmare for Bulgarian journalists, regardless of whether she was killed because of her last aired show or whether it was about violence against a woman,” she said.

Additional reporting by Martin Dimitrov in Sofia