This week officers of the Guardia Civil arrested six people for their involvement in the theft from a jewellery store in Puerto del Carmen in Lanzarote last June.
The investigators do not rule out further arrests and their alleged involvement with other robberies on other islands and on the peninsular.
The detainees allegedly stole jewellery valued at just over three and a half million euros.
According to police sources, the search of the premises after the robbery revealed evidence of screwdrivers and a kickstand that they allegedly could have used to force open the doors.
The security cameras recorded all details of the robbery that was perpetrated within a few minutes, and the robbers were described as very skilled in their actions.
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