How the police would know about any of this stuff is a mystery. I think they found Harriet's 5-year diary when they were packing up her belongings from her desk. Here's some extracts (dates are approximate only):
20/8/2020
Shit, shit, shit. Dawn has shot Malone. Had cunning plan to wrap him in rug and bury him in grave of old man nobody has ever heard of. Burned all the evidence. Phew!
21/8/2020
Bugger. Forgot about gun. Cain said he would bury it in field. I think we got away with it.
13/12/2020
Damn it to hell. Daughter of old man wants him exhumed so she can bury him near to where she lives. Panic stations.
17/12/2020
Will helped me to dig up Malone and rebury him in Home Farm without anyone noticing. Phew!
21/12/2020
Feel like I’m cracking up.
1/3/2021
Found secret cellar in house. Despite being here for years never noticed it before. Have decided to live there forever.
14/3/2021
Stupid Will found my secret cellar. He ruins everything.
20/3/2021
Dawn found cellar. Can get no peace.
25/3/2021
Left cellar. Went for very long walk.
16/8/2021
Retired from vicaring because bored to death by colleague Charles.
1/9/2021
Rejoined police. Much nicer colleague. I 🖤 Swirling.
16/8/2022
Day off tomorrow. Weather forecast gale force winds. Perfect for a spot of quad biking. Can’t wait.