MOSCOW, January 25 (RIA Novosti) - Dutch Queen Beatrix responded to a letter by the mother of Russian opposition activist Alexander Dolmatov, in which she asked the queen for an independent investigation into her son’s death at a Dutch deportation center, the NOS channel said on Friday.

The queen, who is currently on a visit to Singapore, said she was informed about Dolmatov’s death and called it “a great tragedy.”

Dolmatov, an activist with the unregistered Other Russia opposition party whom the Russian authorities wanted to question in connection with a violent opposition rally in Moscow last May, committed suicide in a Rotterdam deportation center on January 17, after the Dutch authorities denied him political asylum. Dolmatov had been in the midst of appealing the decision when he died.

His mother Lyudmila Doronina appealed “to the Queen and a mother of three sons” on Monday to investigate her son’s suicide and prior legal status, in a letter posted on Other Russia leader Eduard Limonov’s LiveJournal blog.

In her letter, Doronina expressed concern that “no one from the Dutch side” has answered any of her questions so far, including on the whereabouts of her son's body and the circumstances surrounding his death. Russia's Foreign Ministry said earlier it was in contact with Dutch officials over the repatriation of Dolmatov's body.