The Stranger Diaries by Elly Griffiths
This is the first in a four-book series introducing DC Harbinder Kaur.

The parallels between a Gothic novel and a crumbling school were genuinely creepy, with a murder scene identical to one in the novel. I enjoyed the main characters – it was refreshing to have a woman of colour as the lead officer in the investigation, and I really warmed to DC Kaur.
Whilst I enjoyed the other books in this short series, for me, The Stranger Diaries was spoiled somewhat by a key reference to old photographs on the school’s wall, showing a group of university students outside Peterhouse College in Cambridge, dated 1832.
That wouldn’t have been possible for another twenty or even thirty years – even the word ‘photography’ wasn’t coined until 1839. I expected some sort of hoax to be uncovered, but no. Easily done when you’re getting carried away during a late-night writing session! Ah well, still a rollicking good read!
Amazon UK https://www.amazon.co.uk/Stranger-Diaries-gripping-Gothic-mystery-ebook/dp/B077XH4CQ3
Amazon US https://www.amazon.com/Stranger-Diaries-gripping-Gothic-mystery-ebook/dp/B077XH4CQ3