Relatives of MH17 crash victims have addressed the Netherlands requesting the UN takes over the investigation into the downing of the passenger plane over Ukraine, blaming the Dutch of mishandling the inquiries into the disaster, media report.

In a letter directed to the Dutch Prime Minister Mark Rutte the relatives of the MH17 crash victims asked for “the UN to appoint a special envoy to take over” the inquiries by the Safety Board and prosecution service.

The copy of the letter written by Van der Goen Attorneys representing the families was cited by Reuters on Friday.

Twenty relatives from Belgium, Germany, the Netherlands and the US accused the Netherlands of “completely botching" the fact-finding investigation and the legal framework of the case, according to the letter.

The victims’ families based their accusations on the fact that the Dutch investigators have been unable to access the crash site, located in eastern Ukraine, torn by internal conflict between Kiev and self-proclaimed Donetsk and Lugansk People’s Republics.

The letter also blamed the investigators for failing to meet international requirements to secure evidence.

READ MORE: Mother of German MH17 crash victim sues Ukraine in EU court

Irritated by the prolonged investigation, in the letter the victims' families said that an international inquiry led by the UN is the only way to identify what brought down the plane and ensure they are taken to court.

"Nobody knows who is doing what," said Bob van der Goen, a spokesman for the law firm which took the case, as quoted by Reuters. "There is no coordination, there is no leadership whatsoever (by) Holland."

According to Reuters, Van der Goen represented relatives of victims of the 1992 El Al jetliner crash in Amsterdam, the 2010 Afriqiyah Airways crash in the Libyan capital Tripoli and the 1977 Pan Am-KLM crash in the Canary Islands that left 583 people dead. The relatives of the victims in the latter case received more than $100,000 each.

The Malaysia Airlines MH17 flight crashed in East Ukraine on July 17. All 298 passengers and crew members on board the Boeing 777 were killed. The victims came 10 nations, while most of the passengers – 193 in total – were from the Netherlands, the second largest number of casualties, 43, was from Malaysia.

"We have done everything we could. In view of the safety situation and the weather, we cannot do anything more right now," Rutte said on Friday as the investigators returned to the Netherlands from the crash site.

Two parallel ongoing investigations into the disaster are led by the Dutch with the first looking into the cause of the crash, and a second - a criminal inquiry.

In September the Security Council of the Netherlands (Dutch Safety Board) released a preliminary report into the disaster which said that the MH17 crash was a result of structural damage caused by a large number of high-energy objects striking the Boeing from the outside.

The criminal investigation by the Joint Investigation Team (JIT) is being led by the Public Prosecution Service of the Dutch Ministry of Justice and also includes Belgium, Ukraine, Australia. Malaysia was left out of the team in November due to its political neutrality, the nation's media reported. The police chief Khalid Abu Bakar said he would head to Amsterdam in December to discuss Malaysia’s participation in the process with JIT members, joined by attorney general Abdul Gani Patail.

READ MORE: Malaysia excluded from MH17 probe – for 'not pointing fingers at Russia'?

"When the crash happened, we did not blame any parties, neither Russia nor Ukraine, as we would like to take a look at the concrete evidence," head associate professor in research and aviation at Kuala Lumpur University, Dr. Mohamed Harridon, told RT.

He added that unlike "western counterparts," Malaysia has taken a “neutral role," and not "pointed fingers at Russia," suggesting that that was the reason for the JIT neglecting the nation’s participation in the investigation.

A number of Western officials blamed Russia for the catastrophe, claiming that it was caused by a surface-to-air missile launched by local militia forces in eastern Ukraine with help from Moscow.

Russia refuted the allegations expressing irritation with the lack of evidence to support the claims. Moscow suggested the UN should appoint a special representative to monitor the investigation.