As reported by a McKinney resident:
I was driving down Eldorado by Ridge last night and a dark green khaki explorer with police lights tried to pull me over. I didn't think it was a police car so I didn't pull over. I called 911 and gave them the license plate number and they ran the tags. Mckinney police and 911 confirmed it was NOT a police officer. I am so glad I did not stop. The car pulled up next to me then and I waved my phone hoping he would get that I was calling the police. He then went on to the next car.
It was a new khaki green explorer. The windows are so dark that you cannot see inside of it at all, even from the front. You also cannot tell that there are police lights on it until he turns them on. Then it looks real and he has the police siren on it also. The tag number is MLL 143. Mckinney police are looking into it and told me to never pull over for an unmarked car if I feel it is not a real one. They said to call 911 immediately and they can verify it for you.
I had both of my toddlers with me so it really shook me up. I am just so glad I didn't pull over. The other car did not pull over either. He finally pulled off Eldorado onto Hillsdale into Stonebridge ranch. I know that you live near there and have other friends nearby, so I thought that I would let you know.
UPDATE: I spoke with Officer Haak with the McKinney Police Department about this incident. He confirmed that this person was a volunteer fire fighter. They are allowed to have lights in their personal cars for times when they are responding to emergency calls. He also confirmed that you should not pull over for an unmarked car if you don't feel it is safe to but this was not in incident of an individual impersonating a police officer.