It was within the now completed Operation rhyme frost that the police conducted several pilot tests to screen images and find surveillance films that capture the same person.
During the tests there has been no requirement that those who have their images processed should have a certain degree of suspicion against them.
"We (have) talked to our legal department and there was their assessment that we could do tests," Niclas Appleby, IT forensic scientist at the National Forensic Center, told Ekot.
The police were approved last year to match facial images against the signaling register, but the Data Inspectorate has said no to the police's test operations with facial recognition at Skavsta airport. The police's use of the American face recognition app Clearview is currently being investigated.