Robert Petrick searched for the words "neck," "snap," "break" and "hold" on an Internet search engine before his wife died, according to prosecutors Wednesday... Investigators continue to find new evidence on computers seized from Robert Petrick's home that prosecutors say support their arguments that Petrick killed his wife.The Google search was the latest in recently discovered evidence found in the 100 million pages of content removed from computers.

I've been predicting for quite some time that Google's "save everything forever" policy will turn them into a treasure trove for prosecutors. While this case doesn't involve a Google subpoena, the idea does not seem far removed. Subpoenas are easier to get then the sort of search warrant executed in this case. Most of the Slashdot commentators miss the point. The point is that this stuff is evidence of someone's thought processes that can be relevant to a trial. Its use will expand.

If a national security letter could be used to obtain all of Google's records, and the police where prepared to manage that amount of data, and the policies allowed them to retain the data and reuse it elsewhere, the impact of that could be quite similar to having police doing background checks on any questionable search term. I do think this is an unlikely scenario. It would be more likely to bring the NSL house of cards crashing down then to succeed. But even without this, once people realize that their search history is legally discoverable its going to have a big chilling effect on how they use the Internet.