with information sharing. Echelon is the result of one such agreement and the information collected is shared AFTER it gets to go through over a dozen electronic filters and a few human ones as over 99% of what they collect is garbage from the intelligence community's viewpoint. The final data that comes through the filters is shared with all the participating countries, how they use it is up to them. However, in many countries it can be used for starting intelligence investigations but can't be submitted as evidence in a court of law unless another copy is obtained in the normal process of legal investigation.

Now for general data, extradition agreement relating to people, materials, and data do exist, but most are on a country to country or a UN Treaty agreement basis. That's how the FBI got that info from the NZ courts on Mega-upload which has now been declared by the NZ courts as unlawfully obtained and not admissible as court evidence.