Speaking on the "Otse Postimehest" ("Live from Postimees") webcast of Postimees, Blankin noted Friday the basic human right to find out the cause of a family member's death, BNS reports.

"It is just like asking 'why are we investigating a murder, since it does not bring the victims back?'" Blankin said on daily Postimees' live broadcast "Otse Postimehest".

"Relatives have the right to demand an investigation, and the state has a duty to investigate...If the immediate subject is unexplored, no firm conclusions can be drawn as to the cause of the disaster," Blankin added, before noting a 2009 expert panel had said that further exploration of the wreck – which lies in – and ensuing further studies were needed before alternative scenarios to the official line could be ruled out.

In 2009, a panel of experts led by Margus Kurm concluded that other scenarios could not be overridden by existing studies – that the wreck needed to be explored and new studies had to be conducted," Blankin said.

The MS Estonia sank with 989 people in a storm on the night of September 28, 1994, while en route from Tallinn to Stockholm. There were 137 survivors; 852 perished, with only 95 bodies recovered.

The official explanation revolves around failure of a bow door due to the strain of the storm-force waves, leading to a breach after the vehicle deck ramp was forced open, causing the sinking.

According to Blankin, a peace of the grave agreement signed by Estonia, Sweden and Finland in 1995 does not interfere with any additional investigation.

"In fact, this agreement is very brief, anyone can find it, and it was even published in the State Gazette (Riigi Teataja) in 1995. There are basically only a couple of points in the agreement, which says three things. First of all, indeed, that the three countries have agreed not to raise the wreck up. There's no more rationale there, just that one specific paragraph," Blankin said.

"Second, the location of the wreck ... must be properly respected. Third, the parties to the agreement must lay down rules in their laws in the event that someone dives for the purpose of looting the wreck, in which case they should be punished. [However,] the peace of the grave agreement does not prevent us from identifying the state of the wreck and the cause of the sinking," Blankin continued. 

Unauthorized dives are not an unknown occurrence at the MS Estonia's resting place, with boats containing suspected wreck-divers intercepted by the authorities.

Wreck diving as a sport has a long pedigree, with the SS Andrea Doria, an Italian liner which sank in 1956 to an initial depth of around 50 meters in U.S. waters, as a particularly prized focus.

The MS Estonia lies at a depth of around 100 meters, about 55 kilometers northwest of the Ristna lighthouse on Hiiumaa, and a somewhat shorter distance south of the Turku archipelago, Finland.

The disaster was investigated by a joint committee of the governments of Estonia, Finland and Sweden in 1994-1997 and by a government committee led by the Estonian Office of the Prosecutor General in 2005-2009. In 1995, Estonia, Finland and Sweden entered into a peace of the grave agreement, which forbids diving in the vicinity of the shipwreck.

The Estonian government missed a deadline imposed by the Tallinn Administrative Court last autumn, by which time it was required to decide on whether to open a new investigation into the causes of the sinking.

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