IMMEDIATELY FOIA the entire encounter. It is likely that they audio recorded the incident, although some departments erase recordings as soon as 2 weeks after they are recorded.
Also, if it was on Meijer's property, they almost definitely also have video of it as well, but they might erase even faster than the police. Asking if they have footage should be your very first concern.
As far as attorneys, Dean Greenblat is the best one in this area that I know of. He's representing theszerdi, and I can personally assure you that he's extremely competent with gun laws, and friendly towards OCers, although he isnt' interested in OCing himself. His number is posted in the info thread, and here it is again for convenience. 248 644 7520