You could consider names like 'Shadowbane' for the killer, 'Victim Vale' for the place where the murders occur, and 'Detective Dusk' who tries to solve the case.
How about 'Spellblade Slayer' for the murderer who uses magic in his killings, 'Enchanted Crypt' as the place of the murders, and 'Wizard Watcher' for the one who tries to stop the murderer using magic of his own.
One could be 'The Shadow Stalker'. It gives a sense of a hidden, menacing figure. Another is 'The Bloodletter', which is quite vivid and implies a violent nature. And 'The Silent Slayer' also works well as it suggests a stealthy and deadly character.
Some good names could be 'The Silent Killer', 'Murder in the Shadows', 'The Deadly Secret'. These names create a sense of mystery and danger which are often associated with murder stories.
For a victim, how about 'Ella Gray'? The name 'Ella' is soft and feminine, which makes her seem more vulnerable, and 'Gray' can add a bit of a dull, tragic undertone. As for a suspect, 'Maxwell Stone' could work. 'Maxwell' sounds strong and confident, and 'Stone' gives an impression of coldness and hardness.
There are quite a few options. For example, 'The Hidden Murderer' is a simple yet effective name. It makes the reader immediately curious about who the hidden murderer is. Another one could be 'Death's Veiled Secret'. This name creates an air of mystery as it suggests that there is a secret related to the death that is veiled or hidden. Also, 'The Unsolved Murder Riddle' is a good choice as it implies that the story is going to be about a murder that is like a riddle waiting to be solved.
You could use names like 'Detective Blackwood'. It gives an air of mystery and professionalism. Another option is 'Victim Vale'. The alliteration makes it catchy and it clearly indicates a key element of the story. Or 'Murderer Malone', which is a bit more straightforward and can create an immediate sense of intrigue.
Names like 'Scarlett' are popular as it gives a sense of mystery and allure. 'Victor' is also a common choice as it can imply a victorious or dominant character, which could be the murderer or the detective. And 'Luna' can be used for a female character, perhaps a witness, as it has a dreamy and somewhat otherworldly quality.
You could use names that have certain connotations. For example, names that sound a bit menacing like 'Damian' or 'Morganna'. Or you can base them on the character's role. If it's a detective, something like 'Sherlock' -esque names. Also, consider using names from different cultures to add an exotic touch.