Lawyers representing the relatives of people who died in the MH17 disaster are being intimidated and the Dutch counter terrorism agency NCTV has offered them extra security, broadcaster RTL Nieuws said on Thursday.

Several lawyers have been followed home and this may be connected to the fact that relatives were allowed to speak in court during last month’s hearings, RTL said. This means the lawyers have had a more prominent role in the case than usual.

The trial resumed in September and for three weeks relatives were able to outline to judges what the tragedy of July 2014 had meant to them.

They were supported in this by a group of eight lawyers who have been given access to all the files held by the public prosecution department.

The lawyers were invited to attend a briefing by the NCTV on September 22, during which NCTV staff said that Russia had being trying to intimidate them and hinder them in their work, RTL reported.

The agency said it does not expect that any physical violence would be used against the lawyers, all of whom declined to be interviewed for the RTL article.

Leiden University researcher Ben de Jong, who specialises in Russian security issues, said the modus operandi is typical. ‘If you see a group as an enemy, because they say negative things about Russia in public or in the media, then you have to do something about it,’ he said. ‘So you intimidate people and try to make them feel insecure in retaliation.’

Three Russians and one Ukrainian have been charged with 298 counts of murder for supplying the Buk missile which the prosecution service says was fired at the Boeing 777. The passenger airliner was shot down over eastern Ukraine en route to Kuala Lumpur from Amsterdam. Russia denies any involvement.