To play the devil’s advocate, it is scientific fact that people are less deterred by gravity of punishment than certainty of punishment. if you understand the police’s job as both preventing crime and investigating crime, than crime prevention is the more important job than crime investigation, because every victim would be the happiest if they never had been a victim. So it is logical, that if a crime happened, you want to investigate and if possible, use the investigation to prevent crime. As perceived certainty is such a good deterrent of crime, you want to be perceived as highly successful with investigations and therefore punishment as highly likely.

So that brings you in the situation where an investigation has a higher value for the police when the investigation is in the news, as a success in that investigation will raise the perceived certainty of punishment more, compared to a “unknown” crime. As the value is higher, the resources spend on it can be higher too, as long as the additional funds are relative to the additional value of the investigation.

It seems immoral to spend more resources on high profile cases, as it seems to value certain lives more but arguably it raises the safety of everyone by making punishment seem more certain.

Obvious counterpoint: If you know that they are doing that, you aren’t perceiving them as successful in the average investigation and there you don’t feel like punishment is certain, or more certain.