A bomb scare at the offices of a small newspaper has been labelled “a direct threat to press freedom” after a story about a mosque angered Muslims in Sweden, prompting death threats.

The threats against Gefle Dagblad (GD) editor Anna Gullberg have been ongoing since last November, when her newspaper published an exposé on apparent links between the Gävle city mosque and the Islamic State.

Now there has been a new threat against her life, with a phone call promising the editor would be injured or killed. A report on the phone call, which has been passed to police, claims the man who made the malicious communication is a “close relative” of mosque Imam Abo Raads. The preacher has often been at the heart of revelations about the mosque made by the newspaper.

After the paper revealed the Imam had “cheered on” the successes of the Islamic State on social media, there was an anonymous tip-off to police that a bomb had been placed in the offices of the paper, and a demand the article be taken down, reports Friatider.

Police searched the premises of the paper but found no device on that occasion.

Writing on Facebook last year, the Imam wrote: “Brothers and sisters, pray to Allah for support for their (sic) Sunni brothers in Iraq, where they are fighting a disastrous war against perfidious sake, kufrs and sinful sake of forces”. A friend replied to his Facebook status: “O Allah, give victory to our brothers in the Islamic State of Iraq and Syria [ISIS]”.

The paper has continued to investigate the mosque since, and so has continued to receive threats. In October the paper revealed men fighting with the Islamic State had been worshippers at the mosque before they left.

It reported in February that a board member of the Mosque uploaded an image of the Islamic State battle flag to his Instagram, with the caption “We Muslims love, honor and raise the flag”.

Friatider reports the remarks of editor Anna Gullberg on the latest threat, when she said: “This is a direct threat to press freedom. The threats have an obvious connection with the publications of Gefle Dagblad“.

She said: “We have an important role in the local community and the GD’s journalists have a vulnerable and tough job.

“Local journalism is under very strong pressure today. Hatred is becoming more common and is a major safety risk on a daily basis for many journalists, especially in social media. This type of personalized targeted threats, I hope that the police will take very seriously”.

Police are investigating but have said the accused denies that he was involved.