sighting high up in space

I was riding with my friend ((witness #1)) from Tahoe to meet his uncle and family traveling in their RV from Stockton. We were to meet in El Dorado Hills for some supplies. It was late, about 10:15pm when we met at his RV. We were all outside on a very clear warm evening, No moon that night you could see billions of stars and easily spot a satellite going by in space, and I did. Being an avid astronomer myself, I pointed almost directly up at the sky and said "look at this satellite going by" So by the time everyone looks up and sees it - out from the south came a fish-tailing light about the same brightness as the satellite. It was fish-tailing from left to right as it went forward in space. And guess what, it was on a collision course with that satellite! ((Uncle's name deleted)) uncles older niece  (sic--cousin to witness??) said "what's that thing below it?" My jaw dropped.. I replied, "I don't know.." We all watched as this weird object made its way with the satellite in it's path. When it got to almost where it looked like they were going to collide.. BOOM! This thing just went crazy, started doing these violent superfast zig zags around the satellite as if it were threatened!! It did that in an instant, and when it did we all screamed at the same time! Look at what we were witnessing way up in space! And I bet we were the only ones to see it. You had to be looking up at the right place at just the right time. Nothing we have will ever reproduce the swift movements of whatever that thing is/was nor does it make any sense to have such vehicles behave like that. After the zig zag attack on the satellite, the craft went back into it's fish-tailing left to right movement as it went forward, heading West, high above the earth. About a half a second-left and a half a second right is about the pulse it was moving at. It seemed like an inefficiant way of travel. Very alien. We watched it fishtail for about a minute until it was too far away to see anymore. You probably won't believe this, but I had a sighting 2 years prior to this in the same ar! ea! With this sighting I am now fully convinced we are NOT alone in the universe.
Date is approximate.  PD