A discarded bicycle near the scene of a robbery at the Strangnas Cathedral during which thieves stole priceless treasures from the Swedish royal regalia, including a jewelled crown. File picture: Pontus Stenberg/TT News Agency via AP

Stockholm - Swedish police have made an arrest in connection with the theft of two 17th-century royal funeral crowns and an orb from a Swedish cathedral last year, prosecutors said on Friday.

"The person was arrested on Thursday evening on suspicion of handling stolen goods," prosecutor Isabelle Bjursten said in a statement.

The suspect was to be assigned an attorney and questioned.

Prosecutors must decide by midday Sunday whether to file a pre-trial detention request for the suspect, who was not identified.

The stolen regalia were recovered early Tuesday in Akersberga, north of Stockholm. Police and prosecutors said then that "everything suggests" that the regalia had been found, but were seeking full confirmation.

The unexpected find resulted in a decision to adjourn the trial of Nicklas Backstrom, the man charged with the theft, to allow further investigations.

Backstrom is charged with stealing a gold funeral crown and an orb made for King Charles IX (1550-1611), and a crystal-studded gold crown made for Charles' second wife, Kristina the Elder.

The items, stolen July 31, were valued at 65 million kronor (7.2 million dollars).

Backstrom has denied the charges although traces of his blood were found in the Strangnas Cathedral, west of Stockholm.

The trial at Eskilstuna district court was scheduled to resume on February 15.

The prosecution, art experts and the church have designated the items as "irreplaceable" and part of the national heritage.

Police and prosecutors have earlier said a second man was also suspected of involvement in the theft. Witnesses said they saw two men flee by bicycle from the cathedral, and then by motorboat on nearby Lake Malaren.