Hi - I’m not sure anyone here understands how we can help... I certainly am in the dark.
Yes, the peak at 16kHz (-85dB) is visible as is another at ¬9.5kHz at what looks like -90dB -- neither looks v. high in amplitude at the measuring point (obviously perceptible however, at -50dBA)
There is no way establishing from afar what generates those noises
If there is suspicion of fould play, isn't this rather a matter for the police?