SOFIA, Bulgaria (AP) — The mother of the suspect arrested for the rape and killing of a Bulgarian television journalist has reportedly said her son admitted the murder to her.

Bulgarian private Nova TV station on Thursday broadcast an interview with Nadezhda Krassimirova, the purported mother of Severin Krassimirov, 21, who was arrested Tuesday in Germany on a European arrest warrant.

She told the broadcaster her son had consumed alcohol and drugs before committing the murder, and that he regretted his actions. The Associated Press could not independently verify her identity.

Krassimirov was arrested outside the city of Hamburg in connection to the murder of Bulgarian TV reporter Viktoria Marinova, 30, who was raped and strangled on Saturday in the northern town of Ruse.

Marinova hosted a show last month featuring two investigative journalists who were detained for their work on suspected fraud involving European Union funds.

While Marinova didn't appear to have been closely involved in the fraud investigation, her show touched on a sensitive subject in Bulgaria, where corruption is endemic.

Bulgarian Interior Minister Mladen Marinov said earlier that investigators had spoken to Marinova's family and friends and "there is no apparent link to her work," but added that investigators are examining all possible leads.

The U.S. State Department on Thursday joined European leaders in urging Bulgarian authorities to investigate her death thoroughly.

"Without prejudging the circumstances of her death, we affirm that violence against journalists anywhere is a threat to freedom of the press and human rights," the State Department told The Associated Press in an emailed response to a query. "A free press strengthens democracy and deserves protection. Further, the U.S. government condemns violence against women in any form."