By Agencies

The body of 30-year-old journalist Viktoria Marinova was found on Saturday in a park in the town of Ruse.

Police in Bulgaria have said a suspect will be released without charge in the murder case of Viktoria Marinova, a journalist who was raped and killed earlier this week.

Earlier on Tuesday, the country's interior ministry said "a Romanian citizen of Ukrainian descent" was taken into custody.

"Our work is continuing. For the time being there are no facts and circumstances that we can announce. The Romanian citizen is to be released," said Teodor Atanasov, the head of Ruse regional police.

The body of 30-year-old Viktoria Marinova was found on Saturday in a park, Ruse regional prosecutor Georgy Georgiev said on Sunday.

Marinova was killed by blows on the head and suffocation, the authorities said, adding that prosecutors were probing all leads - both personal and linked to Marinova's job.

Interior Minister Mladen Marinov later confirmed to journalists that the victim had also been raped. 

READ MORE: Journalist Viktoria Marinova raped and murdered in Bulgaria

According to police sources, the crime did not immediately appear linked to her work, AFP news agency said on Monday.

Following the murder, Prime Minister Boyko Borisov expressed hope the perpetrator would be found.

International organisations called for thorough investigations following the news of her death.

United Nations spokesman Stephane Dujarric said that UN Secretary-General Antonio Guterres was "very concerned" about Marinova's murder, adding that he awaited the conclusions of the investigation into her killing.

European Commission spokesperson Margaritis Schinas said 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".

"We must make sure that journalists everywhere are safe and make their invaluable contributions to our democratic societies," Schinas added.

Her calls were echoed by Reporters Without Borders (RSF) and the Committee to Protect Journalists (CPJ).

"RSF urges the authorities to carry out a serious and thorough investigation to find the perpetrators of this heinous murder," RSF Secretary-General Christophe Deloire said.

"We call for police protection to be provided for the TVN journalists who worked with Viktoria Marinova on the same sensitive report, pending the outcome of the investigation," he added. 

RSF calls for protection for murdered Bulgarian journalist’s colleagues https://t.co/ELDmIEIJGm #ViktoriaMarinova #Bulgaria #noimpunity #endimpunity pic.twitter.com/mZU3Bpy75d

— RSF in English (@RSF_en) October 8, 2018

The CPJ said it was "shocked by the barbaric murder". "Bulgarian authorities must employ all efforts and resources to carry out an exhaustive inquiry and bring to justice those responsible," the media watchdog said in a statement. 

TV host #VictoriaMarinova, 30, was found dead Saturday in #Ruse, #Bulgaria; she had been raped, beaten, and strangled.

CPJ calls on the Bulgarian authorities to conduct a rigorous, thorough investigation into her killing. https://t.co/gc6xjyw19a

— Committee to Protect Journalists (@pressfreedom) October 8, 2018

Marinova was an administrative director of Ruse's small private TVN television and had recently launched a new current events talk show called Detector.

The last episode of the show on September 30 broadcast interviews with investigative journalists Dimitar Stoyanov from the Bivol.bg website and Attila Biro from the Romanian Rise Project, about an investigation of alleged fraud with regards to EU funds linked to big businessmen and politicians.

The pair was briefly detained by police, drawing condemnation from the RSF.

In a statement on their Facebook page, Bivol.bg also called for police protection of Marinova's colleagues.