His expression was one of shock, as if he had only just noticed where he was

Natural Causes by Fife farmer-turned-author James Oswald is the first in the Inspector Mclean series. It is published by Penguin, rrp £7.99. Bury Them Deep, the latest in the series, was published by Headline in February, rrp £14.99.

Ashadow of movement, and instinct kicked in. He ducked, twisting around as a huge man lunged at him. Jethro Callum held a hunting knife in one hand, and moved with a fluid grace quite at odds with his bulk. Never assume a big man will be slow. That was what they’d taught him in self-defence. Mclean dodged the blade, moving in to parry the expected thrust.

But instead of trying to fight, Callum stepped back, reaching up with the knife to his own neck.

“Oh no you don’t!” Mclean leaped forward, knocked the knife out of Callum’s hand. Together they crashed to the floor.

Mclean had the advantage of being on top, but his attacker was a good foot taller and probably half as heavy again. The muscles beneath his leather jacket were like rock, taut and straining. He didn’t so much push Mclean off as fling him bodily away before rolling over and reaching out for the knife.

Mclean pulled a pair of handcuffs out of his pocket, twisting them open as he sprung forward. He slipped on something squelchy on the carpet, losing his balance and pitching onto Callum’s back.

Desperation

They both crashed to the floor again, but this time Mclean managed to get one cuff on. Callum reached out for the knife, fat fingers scraping at the bloody carpet in desperation.

Using the cuff as leverage, Mclean twisted the restrained hand up hard into the point between Callum’s shoulder blades, kneeling on his neck and grinding his face into the carpet.

And still the big man stretched for the knife, thrashing his legs and torso to try and dislodge the heavy weight of detective inspector on his back.

There was no way that he could get control of Callum’s other arm, and neither could he get to the knife before him.

Mclean looked around for something else to use as a weapon, eyes lighting on a china vase sitting on a small oak occasional table just in reach.

He grabbed it, feeling an instant’s regret as he recognised it as a very valuable Clarice Cliff, and brought it smashing down on Callum’s head. The big man grunted, then relaxed onto the floor, unconscious.

Footsteps clattered across the hall outside and Mclean looked around to see DC Macbride appear in the doorway. “Thanks for the help,” he said.

“Spenser recruited him from a street gang over 10 years ago, took him on as a personal bodyguard. He’s been working for the old man in America all that time, which is how he dropped off our radar. And you’ll never guess who one of his known associates was, back in the day.”

“Donnie Murdo?”

“In one. My guess is Murdo was working for Spenser when he ran down Alison. Probably trying to take the heat off the search for Chloe until he’d finished with her.

“What a stupid, petty reason to kill someone.” Grumpy Bob kicked out at an innocent wastepaper basket, sending it and its contents flying in different directions.

“Any reason why he’d suddenly decide to murder his boss?” Mclean nodded towards the hulking form of Jethro Callum.

They were watching him through the one-way mirror that looked into the interview room. He had a good idea why, but it wasn’t a happy place to go. “I guess we’d better ask him.”

“OK, Bob. Let’s get this over with.” Mclean grimaced out of the chair; he’d managed to crack three ribs and had picked up a bruise the size and shape of Poland in the fight.

He began to have some inkling of just how David Brown might have felt before he died.

Formalities

Callum didn’t move when they pushed open the door, neither did he register their presence when Mclean settled himself down gingerly into the chair opposite.

Grumpy Bob unwrapped two tapes and slipped them into the machine, setting it to record their interview, and still the burly chauffeur said nothing.

Mclean went through the formalities, then finally leant forward, resting his elbows on the table between him and the murderer.

“Why did you kill Gavin Spenser, Mr Callum?” Slowly, the bodyguard lifted his head. He seemed to have difficulty focusing his eyes, and his expression was one of shock, as if he had only just noticed where he was.

“Who are you?” he asked.

“We’ve been through all that, Mr Callum. I’m Detective Inspector Mclean, and this is my colleague, Detective Sergeant Laird.”

“Where am I?” Callum pulled at his cuffs. “Why am I here?”

“Are you seriously expecting me to believe you don’t know, Mr Callum?” Mclean studied the bodyguard’s face.

It was something only a mother could love, scarred from numerous fights, nose flat and squint, eyes just slightly too close together to have any hope of conveying intelligence. But there was something in there, lurking behind the bewilderment. He could sense it, and in that instant, Mclean knew that it sensed him too.

Callum stopped straining against his handcuffs, instead slumping forward as his whole body relaxed.

“I know you. I’ve smelled you before. You drew the circle around yourself but it won’t protect you from me. We’re destined to be together, you and I. It’s in your blood. His blood.”

Where Callum’s earlier words had been slurred and hesitant, now he spoke clearly, clipped. It was a voice of control and power. Another person entirely.

“Why did you kill Gavin Spenser?” Mclean repeated his earlier question.

“He was their leader. The last one. I killed him to be free.”

“The last one? You’ve killed others?”

“You know who I’ve killed, inspector. And you know they all deserved to die.”

“No, I don’t. Who did you kill? What were their names? Why did they deserve to die?”

Frightened

Callum stared straight at him, face set like stone. And then his features softened again, as if he were remembering something highly emotive. His eyes went wide and his mouth dropped open.

He looked left and right, around the small interview room with panicked twists of the head. He pulled at his restraints once, twice, then realising it was hopeless, slumped forwards.

Tears filled his eyes, rolling over the scars on his cheeks as he started to mumble in a frightened, childlike voice. “Ohgodohgodohgod.”

Mclean looked at the big man, rocking gently in his chair. Had his hands not been in cuffs, he was sure Callum would have curled up in a ball in the corner of the room.

There had been something there, briefly, but now whatever mad instinct had driven the man to commit such a brutal murder was gone, and he was left alone with the memory of what he had done.

“Interview suspended at 21.52.” Mclean stood up, gasping as his ribs protested, and clicked off the tape recorder. “Have him escorted back to the cells. We’ll try again in the morning.”

More tomorrow.