English mystery writer William Edward Vickers (1889-1965) was best known under his pen name Roy Vickers, although he also wrote under the names David Durham, Sefton Kyle, and John Spencer. He found his literary stride when he published his short story, "The Rubber Trumpet," the first of over three dozen stories originally published in Pearson's Magazine and featuring the fictitious Department of Dead Ends division of Scotland Yard (a precursor to TV's "Cold Case," if you will). Many of these are inverted mysteries, with the crime and perpetrators being known and the crime solved as much by luck and perseverance than brilliant detection.
The central sleuth in Vickers' Department of Dead Ends stories started as being Superintendent Tarrant and in the later stories switched to Inspector Rason. However, Vickers also wrote eight novels in a more traditional procedural style featuring Detective-Inspector Peter Curwen. Find the Innocent was the final Curwen installment, published in 1959. He's described by one character as being "large, rotund and homely, looking like a successful local auctioneer who contemplates retirement."
Three scientists, Eddis, Stranack and Canvey, are all suspects in the murder of their employer, Mr. "WillyBee" Brengast, who had refused to grant them royalties on their inventions. The trio work and live together at WillyBee Products Ltd., yet they detest one another. Each man gives the same story to the police—each claims the same alibi, that he was the one to stay behind alone with the victim while the other two men went into town together. It's obvious to Inspector Curwen that one man must be guilty and the other two abetting, but which is which? Complicating matters are the victim's beautiful young widow whose one-night stand with one of the scientists plays a key role, and the victim's brainy niece who "helps" Inspector Curwen while falling for another of the suspects.
I've not read much of Vickers' output, but I came across one criticism that his novels paled in comparison to his stories, and I think I can understand why that might be the case. The premise of Find the Innocent is promising—three suspects who give the same story with little or no evidence to prove or disprove which one is guilty—but I think the novel (novella, actually, as it's on the short side) would have worked even better as a shorter story.