Authorities in Bulgaria are working for establish whether the brutal rape and murder of an investigative journalist was linked to her work.

Viktoria Marinova's body was discovered in the northern town of Ruse on Saturday.

The 30-year-old had been reporting on alleged corruption involving big businessmen, politicians and the use of EU funds.

Her badly-beaten body was found in a park by the River Danube.

Ruse prosecutor Georgy Georgiev said she had suffered blows to her head and had been suffocated.

He said her mobile phone, car keys, glasses and some of her clothes were missing.

The country's Interior Minister Mladen Marinov confirmed she had been raped.

He said there was currently no evidence to suggest the murder was related to Ms Marinova's work adding that authorities had no information that she had been threatened.

Bulgarian Prime Minister Boyko Borisov said it is " just a matter of time" before the murderer is found - after investigators uncovered a large amount of evidence - including DNA.

Investigative journalism

Ms Marinova had been presenting a newly re-launched news programme called 'Detector' on Bulgarian television.

The last episode saw her interviewing two investigative journalists - Dimitar Stoyanov from the Bivol.bg website and Attila Biro from the Romanian Rise Project  - on the alleged corruption and misuse of EU funds.

Bivol.bg owner Asen Yordanov has said he received credible information that his journalists were in danger due to their work.

"Viktoria's death, the brutal manner in which she was killed, is an execution," he said.

"It was meant to serve as an example, something like a warning."

Increased attacks

The Organisation for Security and Co-operation in Europe (OSCE) expressed its shock and condemnation at the crime and called for a thorough investigation.

Harlem Desir, OSCE representative on freedom of the media said there has been trend of increased attacks against female journalists in recent years, and warned that their safety is of paramount importance.

"I am deeply saddened by this horrific murder and express my deep condolences to her family at this difficult time," he said.

“I will closely follow the investigation opened by the authorities."

"I urge them to swiftly identify and bring to justice those responsible and to clearly determine whether this attack was linked to her work.”

Rigorous investigation

The Committee to Protect Journalists (CPJ) called on Bulgarian authorities to "conduct a rigorous, thorough investigation" into the murder.

"CPJ is shocked by the barbaric murder of journalist Victoria Marinova," said the organisation's EU representative Tom Gibson.

"Bulgarian authorities must employ all efforts and resources to carry out an exhaustive inquiry and bring to justice those responsible."

Journalist murders

The group noted that Ms Marinova is the third European journalist to be murdered in the past year.

Prominent Maltese investigative journalist and blogger Daphne Caruana Galizia was killed in a car bombing attack near her home in Northern Malta in October 2017.

Slovak investigative journalist Ján Kuciak was shot dead in February 2018 in Slovakia.

Additional reporting from IRN ...

If you or someone you know has been affected by sexual violence you can contact the National Rape Crisis Centres’ 24-Hour Helpline on 1800 77 8888.