Replying to I think I've been witnessing a major drug deal for 9 months

7 out of 10 times i drive my gf home, or when we are in my car at her house past 1 am we see this little red car drive up to her neighbors across the street, stop at the mailbox and take off. We never really though much of it, just thinking it was a strange thing until recently. Yesterday i noticed that I have never seen the curtains open or anyone home, the curtains are made of a reflective material. well tonight i pulled in her sub and the car was just chillen, as i got closer it drove off really fast, i went to the end of the street to turn around so i wouldnt pull in her driveway and shine my lights in my gf's parents room, and i passed the car at the end of the street going to the opposite direction. i stopped in front of my gf's house, which is right in front of said mailbox, and as we were saying our goodbyes the car came up, stopped at the mailbox for less than 5 seconds, and speed off again. my gf said she was scared to go in, so i waited until she got inside to leave. she just texted me that shes really scared now because it happens so much and we realized there is probably a grow op across the street, and we are in Detroit.
Thoughts??