This mystery Bea has to solve pretty much on her own, her usual helpers being otherwise occupied. She still comes up trumps though. A False Alarm (The Bea Abbot Agency Mysteries Book 7) by Veronica Heley 📚:

Someone set a tripwire across the top of the staircase in Sir Lucas’s apartment block causing him to fall head-long and break his arm. A malicious prank … or something much worse?

Book cover: A False Alarm.