Muckrock user Evan Anderson sent a public records request to the Boston Police Department asking for records of communication between BPD and the NSA. Here's what the BPD (finally) wrote back:

The emails have been compiled (not yet redacted) and there are literally hundreds of them. Many of them contain "Happy Birthday" emails that go back and forth between multiple people. We are wondering if you are okay with us setting those emails aside as it will take time (and expense) to go through them to redact them.

Evan said sure, eliminate the "Happy Birthday" emails. On November 7, 2014 the BPD provided a cost estimate for the emails: $402.50. I just chipped in fifty bucks of my personal money because I really want to see these emails. If you do, too, consider contributing here. My guess is that there are going to be lots of redactions, but it should be interesting nonetheless.