Bulgarian media reports said that over the past year Marinova had reported on an ongoing investigation into alleged corruption involving European Union funds for the broadcaster TVN. Margaritis Schinas, spokesman for European Commission President Jean-Claude Juncker, said Monday that the commission expected "a swift and thorough investigation. that will bring those responsible to justice and clarify whether this attack was linked to her work".
A Romanian citizen detained as part of an investigation into the murder of Bulgarian TV journalist Viktoria Marinova was released without charge on Tuesday night.
"There is physical evidence to link to the murder", Marinov said on Wednesday.
Local people held a candlelight vigil overnight and many left flowers to commemorate Marinova, who left a seven-year-old daughter.
But even as investigators worked to establish a motive and apprehend a suspect, competing narratives emerged about whether Marinova had been targeted for her journalism or whether she was the victim of a random crime.
In a statement from the United Nations cultural agency's headquarters in Paris, Azoulay added: "Attacks on journalists erode the fundamental human right to freedom of expression and its corollaries, press freedom and free access to information".
Biro told the AP that he had never met Marinova - he said one of her colleagues had interviewed him and Stoyanov about their work.
In a segment aired on September 30, Marinova interviewed two Romanian journalists who were investigating several politicians and businessmen for alleged corruption of European Union funds.
The first episode of her programme, aired on September 30, featured an investigation into fraud allegations against oligarchs and politicians.
Marinova is the third journalist murdered in the European Union within the past year, Reuters reported. "It was meant to serve as an example, something like a warning".
Bulgarian police, however, said they are considering all possible scenarios and examining possible links to both her personal and professional life. He said there was no information that she had been threatened. The journalist said he and his coworkers feared for their safety.