A prisoner who later tested positive for Covid-19 attended an Auckland court in person on Friday

He's one of three mystery cases announced today.

The man appeared in the Manukau District Court because no technology was available for him to appear remotely.

More than a dozen people are now regarded as contacts, and the court, a nearby custody unit and police vehicles had to be deep-cleaned.

The man's in custody at Mt Eden prison.

Investigations are underway to find out how he picked up the virus before he was arrested.