Bones and Silence, by Reginald Hill

Andrew Dalziel is looking out the back window of his house late one
evening when he sees a murder committed in the house just behind. He
dashes over and arrests the man with the gun, a local builder named Swain.
His wife is dead, shot through the head; Swain claims that she was trying
to commit suicide, and that he was trying to take the gun away when she
shot herself. His story is corroborated by the other man present, a
fellow named Waterson with whom Mrs. Swain has evidently been having an
affair.

But Dalziel knows what he saw, and he’s certain that it was murder.
Others, notably the Chief Constable, are less sure–in fact, they think
he’s flat out wrong–and Dalziel had been drinking.

While Dalziel’s doggedly pursuing a murder verdict nobody else believes
in, Pascoe is dealing with a series of letters Dalziel’s been sent, from
a woman who aims to kill herself. Not immediately, but some time in the
near future. The letters are anonymous, but we know she has to be
someone we’ve met in the course of the book, so who is she?

I liked it. But if you’ve been following along for the last couple of
months, you knew that. I must say, it’s a pleasure to read somebody as
consistently good as Hill.