Sharing information have with other agencies within the legal boundaries (warrants generally) and in a transparent way is fine.
What is not fine is:
1) encouraging the police to do illegal mass surveillance of citizens, too, with Stingrays and other methods
2) use information obtained in an illegal way (such as NSA spying on Americans) to do parallel construction by telling cops exactly who to stop at check points because they already know through illegal spying that he committed a crime, and then using that in Court, and saying they find out about his crime at a regular traffic stop.
What is not fine is:
1) encouraging the police to do illegal mass surveillance of citizens, too, with Stingrays and other methods
2) use information obtained in an illegal way (such as NSA spying on Americans) to do parallel construction by telling cops exactly who to stop at check points because they already know through illegal spying that he committed a crime, and then using that in Court, and saying they find out about his crime at a regular traffic stop.