Prosecutor Isabelle Bjursten said she believes the unnamed 26-year-old "is one of the people who performed the theft" of the Swedish royal treasures, dating from 1611. The man's DNA was found on the regalia, Bjursten said in a statement.
In February, Johan Nicklas Backstrom was given four-and-a-half years in prison for stealing two crowns and an orb used at the funerals of King Karl IX and Queen Kristina. The jewels had been on display in Strangnas Cathedral.
Backstrom had confessed to stealing the items on July 31 but declined to say if he had accomplices. The jewels, which are estimated to be worth 65 million kronor ($6.7 million), were discovered Feb. 5 in a garbage bin north of Stockholm.
The heist made international headlines because two thieves were seen dashing away from the 13th-century red-brick church on stolen bicycles and then fled by motorboat via the vast system of lakes west of Stockholm.
The treasures were used as funeral regalia, which were placed inside or on top of a coffin to symbolize a deceased royal's identity and social ranking. While some funeral regalia are kept in the cathedrals of Strangnas, Uppsala and Vasteras, Sweden's crown jewels are in vaults under the Royal Castle in Stockholm.
The trial is set to start May 27.