In 1964 in Dallas a baby named Andrew saw his mother and her lover murdered in front of him. His father, a professional killer, disappeared at the same time.

The conclusion was obvious.

Twenty-six years later, in Ryan David Jahn’s The Gentle Assassin (Pan, £7.99), Andrew decides that he can never truly begin living his own life until he has exorcised that trauma.

He’s going to track down his father and kill him. But the old man, when he finally meets him, isn’t what he was expecting at all.

Perhaps best described as an emotional thriller, much of the action of this grim and gripping story takes place in the heads of the two men as they try to work out what they feel about each other — and themselves — and what they’re going to do about it.

Maryland teenager Sylvie tells the peculiar story of her young life in Help For the Haunted by John Searles (Sphere, £7.99). Her parents are devoutly Christian ghost-busters whose clients are tormented by evil spirits.

Or else they’re blasphemous and money-chasing frauds, depending on who you ask.

When they’re murdered in a local church, only young Sylvie can identify their deranged killer. But how much of what she remembers of that night is knowledge and how much is merely what she thinks ought to be true?

It’s the same crucial distinction, of course, which has defined and divided her family for decades.

Searles adeptly merges an eerily atmospheric psychological thriller with a beautifully written coming-of-age story about belief and disbelief and how children emerge, or don’t, from their parents’ shadows.

Building Hadrian’s Wall is an unpopular posting for soldiers of the Roman Empire in Tabula Rasa by Ruth Downie (Bloomsbury, £18.99). The weather’s terrible, the natives are hostile and rebellious and there’s almost nothing to spend your wages on.

Army doctor Gaius Ruso and his British wife Tilla are looking forward to returning to more civilised parts.

But when Ruso’s clerk goes missing and the subsequent disappearance of a local child threatens to reignite the anti-imperialist resistance, it’s obviously another case for reluctant amateur sleuths Ruso and his wife.

I find this pair the most attractive and credible of the fictional Roman detectives and this instalment is historically fascinating, politically complex and properly mysterious.

John Martin’s Crime Scene: Britain and Ireland (Five Leaves, £9.99) isn’t crime fiction but any crime fan who is constantly on the lookout for their next good read will want a copy of this neat, inexpensive but authoritative guidebook.

Dividing Britain and Ireland into 13 regions, Martin outlines the work of hundreds of authors whose novels have an identifiable geographical setting.

So if, for instance, you fancy reading a mystery or a thriller set in “Edinburgh and the Borders,” you’ll find mini-essays on more than 20 crime writers whose detectives operate in that area.

The aim of his book, says Martin, is to encourage people to discover new authors by “whetting the appetite.”

He succeeds admirably.