Fear the fruit
It looks like it was Apple that twisted the arms of coppers to get the house of Gizmodo editor raided. According to documents that were unsealed over the weekend, Apple attorney George Riley told detectives that the publication of evidence of the device by Gizmodo was immensely damaging.
He said that people that would have otherwise purchased a currently existing Apple product would wait for the next item to be released, thereby hurting overall sales and negatively effecting Apple's earnings.
However since the article had been published, it was not going to resolve the situation by arresting anyone. At that point it had the iPhone prototype back, although Gizmodo might have made a bit of legal mistake of asking Apple to prove that it was its prototype before handing it over.
Apple CEO Steve Jobs personally contacted Gizmodo editor Brian Lam to request the 4G phone's return on April 19, the day the story was published, but Lam refused to do so, unless the company provided "confirmation that it is real, from Apple, officially.”
It is clear from the documents that pressure was coming from Apple to do a raid and its laywers were screaming that a “crime” had been committed. In fact it seems more that Apple wanted to send a message to the tame IT press that it had to tow the line or it would use its influence.
It will be interesting to see if a higher court over turns the search warrant as illegal.