Easy. Since I don't know where you live, the red light camera could be a possibility, but most counties are required to post a large conspicuous sign that warns drivers that the intersection has a red light camera, if it was at night you would of definatley noticed a distinctive flash as you drove through it, as they need to be able to id you as the driver for the ticket to hold up in court.
What seems much more likely is the cop either saw you or more likely saw from you speed and position to the intersection that you just ran the light, if he saw you he did you a solid cause thats a real easy summons that hes not gonna feel the least bit guilty about writing. He was definately following you for a few reasons, in is mind there was a good chance that you were drunk and wanted to see if he could observe any behavior in your driving that would confirm his suspicion. Since you obviously were on his sh*t list for running the light, he was definately running your tags to make sure the car is clean and also probably looking for an excuse to pull you over and cite you for something, (busted license plate light) dark tints, loud exhaust whatever anything. Or another definate possibility is that he pulled out at first cause he was gonna light you up and then thought about it and decided to let you slide probably because u were now doing about 2 under the limit in the right lane.. in other words maybe he just thought you somehow just missed light by accident and then decided to let you slide.
Either way, no there is no way that you can or have to worry about getting a ticket from the cop. Its not possible. If you drive by the intersection often next time check to see if there is a big white box mounted on one of the vertical poles with a sign that says red light camera in effect. If thats the case ya your gonna have to pay the man a little early taxes this year.
Either way dude don't run lights its a great way to get dead and get other people dead. Im an EMT and after some of the kinda **** i've seen cause someone does something stupid on the road, even with a lightbar on my car I still sit through the same 5 minutes red light on the deserted road at 3 in the morning.
But as far as the ticket no your fine. don't worry
ETA: to the people that are telling you yes they are simply wrong. There are literally dozens upon dozens of rulings all over the country of different counties trying all sorts of ways to cite people for just about anything without having to pull them over. Yes high speed chases are a huge problem and one of the first thing that gets pounded into your head as soon as your enter the academy is there is absolutely nothing routine about a routine traffic stop, its is almost always the single most dangerous situation of your average suburban cops entire shift. Believe me if they could do it they would. But they can't. Back in the day, the southern states would nail people for speeding while overflying the roadways (which they often still do) and then just have a radio car pull up and take down a plate and thats it. They all got thrown out the second they hit a courtroom. They a few years later when the Jersey Tpke opened you would get a toll ticket when you got on and then you'd pay a certain amout when you got off, and for a while they state would compare the times on the ticket and send out thousands of speeding tickets to anyone that reached the exit faster then was possible by doing the speed limit. Those actually got all the way up to an appeals court I believe before they got tossed along with every ticket they had written in the same way up to that point. Even these red light cameras, if you ever read the laws about there use, they are only allowed to be put up in very specific intersections that fail certain safety guidlines, whether it was a certian amount of MVA's at that street in a year, or a 50 or 55 limit leading up to the light, or there have been a lot of car vs pedestrian fatalities in the area, even then they have to warn you for a certain amount of time that the camera is going up, then when they install it they cannot legally change the time that the light stays yellow to try to pull in a few more bucks which some counties were trying to do in the begining, also there insanely easy to have thrown out if your willing ot take the time to show up for court. The majority of tickets are just pled guilty and mailed in with a fine which is just the way the county or city likes it. If you ever actually show up for a traffic ticket youll be shocked how thrilled they are to get you to plead it down to some literally anythign liek a 10 broken taillight ticket, anythign to not have to waste the time and money to stand in front of a judge and fight the ticket. and if they even see you walk in with a lawyer for a routine traffic violation forget it they wont even waste their time, there better off just citing everyone and hoping theyll just check off the guilty box and pay their tax like a good citizen.
Think about it for half a second, lets say you get a ticket in the mail from this cop, you go to court. first words out of your mouth, officer can you please identify who the driver of the vehicle was during the time you witnessed the violation, a description would be fine, drivers license number, name, adress, anything. clank clank, case dismissed with the courts apologies, give me a break guys.
Think about how the public would see it, cops to lazy to do traffic stops, the second a felon or some guy with a warrant gets one of those tickets, and then goes on to commit another crime, they wont even bother asking for the cheifs head on a platter, they will just start getting everyone fired. not gonna happen
I hurt someones feelings once and have a lot of friends that get to do it for a living