After the murder of their best friend, a group of regular city guys struggle to find the suspect but unearth secrets about their friend and a conspiracy to take over the city.

A logline should reveal specific characters, not hide them in general situations. So there's not just a conspiracy to take over the city, there is a specific conspirator. Who is the villain trying to take over the city? A politician? A mobster? Monty Python? Who?

Thanks for the comments. I accept the advice about 'city boys'

If they are regular you don't need to say regular, just say city boys, however I would narrow the logline to one main character to focus on if possible.

you can take out struggle to find the suspect, it doesn't really add anything extra.