Here is my thoughts.
First look at the crime scene before considering any of the allegations about calls, boyfriend, drugs etc. that the police did release.
1) Vehicle approached by an individual.
2) That individual had a gun and was prepared to use it. That inference can be drawn from the fact that she was shot as she started to drive away and the assailant was still next to the vehicle. His exact location at the time of the shot is unclear because we do not know if he was right or left handed. In either case the shot was fired in the time that she put the car in drive and started to move. Likely one or two seconds. That indicates that the assailant was prepared to use deadly force to prevent her from leaving, rather or not the gun was drawn before or after she started to shift the transmission.
3) The angle of the shot indicates that the shot was likely not aimed. The proximity of the shooter would be difficult to aim at that angle and if the shooter was aiming the choice to shoot at the angle and direction does not make sense because if the vehicle is moving away a flatter trajectory would make more sense.
4) Due to the trajectory it appears that the shot was accidental or at least premature due to poor choice of trajectory.
5) The accidental firing is supported by the fact that only one shot was fired. If the shooter intended to shoot her they would have fire more shots as she drove away. It is unlikely that they knew rather or not she had been hit after the first shot and it would have been impossible for the shooter to know if it was a fatal shot. If the shooter intended to kill her he would have fired more shots while she was still close by and taken better aim or at the least immediately gotten in their car and pursued them to finish the job. They would not want a witness.
6) If it was a robbery by a known assailant would have immediately pursued to determine her condition or if she was going to report the crime.
7) If it was an unknown assailant that she would not be able to identify they would have fled the scene. A robber does not want to get mixed up with an attempted murder charge, no matter what they were stealing. I can't imagine any robber thinking she had enough money to steal that it would be enough to stick around after the shot was fired and people's attention were drawn to the scene.
8) The shooter clearly had great interest in determining rather or not she was hit because they risked being identified in order to remain there and observe the consequences of the shot.
9) The most reasonable conclusion, based on their watching her leave and then pursuing her only after after her vehicle stopped across the street indicates that the shooter was determining rather or not to pursue her depending on rather or not she had been hit. They were not concerned about her fleeing the scene nor immediately perusing her. Their thought would have been 1) if she was hit she would not get far or 2) if she was not hit they would either be able to find her even if they lost sight of the vehicle or if she was not hit there would be no repercussions. That indicates the shooter either knew that she would not report the incident, did not have concerns about law enforcement if she did report it or had access to a way of finding her if she fled.
10) Then there is the fact that after the vehicle stopped the shooter put her vehicle into park. The vehicle had already stopped. A thief would have just taken what they wanted and left as quickly as possible. They would have no reason to put the vehicle in park. That means that either the shooter intended to kill her or expected that he may be there for some time and wanted to make it safe for himself. Since his earlier actions do not indicate an intentional murder that means he made the conscious choice take the time to asses her condition and decide what to do.
11) After deciding that she was dead or at least mortally wounded he then took the some item, likely the purse. Why the purse if it is already determined that his intent was not simply to rob her. So the taking of the purse was for some other purpose. I suggest it was to make it look like a robbery.
12) There were no fingerprints to match profiles on file. If the prints have been re-run recently without a match makes it more likely than not that the shooter did not leave any usable prints. This again indicates a fairly high level of sophistication, to either not leave any prints or to remove them.
To me all of this points to the shooter being a Law Enforcement Officer. They are a person that would have a reason to approach a vehicle sitting in a parking lot and would have been armed with a hand gun. The position the shot was fired is where a LEO would stand when talking to someone in a running vehicle. The shooter appeared to have little concern about her reporting him and did not act like someone committing an armed robber on a stranger. If she was intoxicated and attempting to flee he would be justified in pulling his gun and discharging his gun may have also been allowed if she was arguably a fleeing felon or an imminent risk to others. I suspect that it was a accidental discharge as he drew his gun and he watched to get her license number so he could locate her later. When her vehicle stopped he than went over to asses the situation. They would have been trained to secure the vehicle after it stopped and before proceeding to asses the situation. It appears that he stole the purse to stage the scene as a robbery. What would be most helpful is the security footage of the assailant approaching the vehicle. My experience is that LEOs approaching an unknown vehicle invariably touch the trunk hood to leave a fingerprint. In this situation the LEO would know this and would have wiped the area to remove the fingerprint. If the police released the video it could be determined if the assailant touched the rear of the vehicle as he approached and/or wiped the rear of the vehicle before leaving the area. Either of those wold indicate a LEO. Even if the video did not capture those acts, determining if the rear of the vehicle had been wiped clean. If the left rear of the vehicle was cleaner than the rest that would indicate a LEO.
The fact that no video has been released, the photo of her car is cropped so you can not see left rear rear of trunk but have talked about her personal problems, indicates to me that the investigators have seen those tells and are suppressing the video as it indicates a LEO in the incident and are trying to point suspicion in other directions..
