Because almost every IP address has been assigned to a company, government, agency or ISP (internet service provider) this helps narrow down which network the messages in this case came from.

BBC: Email trail helped FBI crack Petraeus case

The e-mails, and the identity of their senders, were passed on to Malaysian police by a compliant ISP (Internet service provider), but Malaysians continued to use the Web as their only way of bypassing the government-controlled print media.

CNN: Malaysian hackers may face indefinite detention

It can go up if there needs to be another court order brought on an Internet Service Provider (ISP).

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