An egotistical detective fights to save his reputation when a series of religious killings threaten to show the community his true colours.

It's not just a matter of clarity, it's a matter or marketing: the linkage of the crimes to the 10 commandments is your story schtick, your hook, a premise that distinguishes your story from the 1,001 other serial murder mystery scripts piled up script reader's desks.

I will attempt to get it in. Thank you for the feedback.

Oh, then the logline ought to say so.

The killings relate to the Ten Commandments with the killer leaving clues lead from the Bible.

"Religious killings" is ambiguous. Does that mean hate crimes against people of a particular religion (such as Jewish or Islamic)? Or are the perpetrators members of a religious cult?

Or all of the above?

When a number of religious killings plague his city, an egotistical detective sets to work on the case hoping to bring his celebrity status back.

Due to an egotistical detective's past work, the city is at its lowest crime rate however as the police become redundant a set of religious killings arise forcing him to protect this city once again.

When a set of religious murders occur in a city with little crime, an egotistical detective is tasked with stopping the spree before the killer completes his onslaught.

Any of these work?