Obidkhon Nazarov, a Muslim cleric also known as Obidkhon Sobitkhony who was living as a refugee in Sweden, was shot in the back of the head and seriously injured in the northern Swedish town of Strömsund in February 2012.
An international arrest warrant issued against a 37-year-old Uzbek led to his arrest in Russia, the Swedish prosecutor in charge of the case, Krister Petersson, explained to the AFP news wire on Wednesday.
“Moscow police arrested him at the beginning of the year. The man was placed in custody pending his extradition,” Russia's interior ministry confirmed in a statement.
On Tuesday, “he was handed over to a Swedish delegation at Sheremetyevo airport” in Moscow, it added.
The Swedish prosecutor said the judicial proceedings against the man had yet to be determined.
Asked by news agency TT whether he suspected the regime of Uzbek President Islam Karimov of ordering the assassination attempt, Petersson replied “yes.”
An Uzbek man and woman were tried in Sweden of aiding and abetting the attack but were acquitted in 2013, he said.
Nazarov had been living openly in Sweden, where he regularly criticised the Uzbek authorities.
A documentary aired by Uzbek state television in May 2010 accused him of masterminding a series of high-profile killings in 2009, as well as a 2004 suicide bombing at the US embassy.
He spent two years in a coma after the attempt on his life, and is still being cared for at a secret location.