LONDON (AP) -- A man British police are calling the "librarian" of a child-porn archive has pleaded guilty to sending indecent images of children to subscribers in more than 30 countries.

A judge has given 27-year-old Philip Thompson an indeterminate prison sentence of at least three years and nine months. He must prove he is not a risk to society before he can be released.

Thompson is accused of amassing nearly 250,000 images in an archive he controlled from two computers in his mother's house.

Police have identified 360 people worldwide suspected of involvement in the ring; 50 have been arrested in Britain.

Lawyer Brian Russell says Thompson has cooperated with police since his arrest in February.

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