I agree that stabbing or strangulation is much likelier than murder by firearm.
I apologise if my post wasn't very clear - "sonic boom" sounds like the kind of thing you would expect to hear upon a comet imploding into the surface of the earth
All I meant was that many firearms are so powerful that when they are discharged and the bullet exits the barrel, it creates a sonic boom as it travels. Wikipedia's definition of a sonic boom: "A sonic boom is the sound associated with the shock waves created by an object traveling through the air faster than the speed of sound. Sonic booms generate enormous amounts of sound energy, sounding much like an explosion. The crack of a supersonic bullet passing overhead is an example of a sonic boom in miniature."
It is the pressure behind the bullet (caused by hot gas from ignited gunpowder) that creates the "gunshot" sound. When a silencer is attached to a firearm, it allows the hot gas to expand into a much larger space, so the residual noise is lessened. That said, it would still more than likely create enough noise to be detected. This is all speculation on my behalf and I am happy to be proven wrong (well, not "happy", but you know what I mean) - I simply think it is unlikely.
The basis of my opinion on this comes from nothing but a personal devotion to and interest in science and forensics. I am certainly not an expert.