step,’ the psychologist suggested. ‘What you want to know is the identity of the person who shot three men in their white Mercedes cars.’
‘Person or persons,’ Lorimer replied glumly.
Solly shook his head. ‘No, you’re looking for one person, Lorimer,’ he said firmly. ‘And to find that person you should be asking yourself why anyone would want to kill these men in the first place.’
‘You make it sound very simple,’ Lorimer sighed.
‘Let’s look at what you have on the Pattison case. The man has been caught on CCTV camera leaving Blythswood Square in the company of a person we think may be a prostitute. With me so far?’
Lorimer nodded, trying to suppress a yawn. He’d been over and over this territory till his head swam.
‘Why would a street girl want to kill men who came to them for sex?’ Solly asked.
Lorimer frowned. ‘D’you really want an answer to that?’
‘Yes. Give me any reason why someone kills another person.’
‘Money, drugs, falling out, spite … ’ He yawned for real now.
‘Or, perhaps, some notion of revenge?’
‘What are you cooking up in that brainy head of yours, pal?’ Lorimer smiled despite himself as they headed around the corner towards the university chapel.
‘It’s not that difficult, really,’ Solly replied with his customary modesty. ‘A woman with a gun who targets specific victims has an agenda. Agreed?’
‘Agreed,’ Lorimer said, ‘though we don’t know if the perpetrator was a woman.’
‘Let’s say it was,’ Solly came back firmly. ‘The last known person with Mr Pattison was a woman, from the image of her on that CCTV footage. Now, if a woman sets out to kill men who pick up prostitutes, there has to be a reason for it, doesn’t there?’
‘What on earth are you suggesting?’ Lorimer asked, frowning.
Solly stopped at the foot of the steps leading up to the chapel and turned to his friend, his hands spread out as he began to explain.
‘If a woman wants to kill someone over and over again like that she must be under some kind of compulsion. Not necessarily one that afflicts her mental state.’ He paused for a moment as though searching for the right words. ‘I think you should be looking for someone who has a deep-seated grudge against someone she doesn’t even know.’
‘What?’
‘Doesn’t it stand to reason?’ Solly asked. ‘All she knows is that her intended victim picks up prostitutes in a particular type of white car. She can’t possibly know his identity or else she wouldn’t have killed three times already.’
‘Unless she’s a prize nutter,’ Lorimer put it, glad to see the psychologist wince at his political incorrectness. The two men climbed the stone steps and entered the chapel. Rays of sunlight from the stained glass windows made shapes of colour dance across the ancient flagstones. All was quiet within, save for the sound of their echoing footsteps.
‘Let’s say that she is not,’ Solly continued, sitting down in a row of wooden seats that faced the main altar. ‘The killings are planned and show an orderly sort of mind. Now,’ he went on, wagging a professorial finger, ‘most of these women are in thrall to drugs and often not capable of doing anything at all like this, agreed?’
‘Ye-es,’ Lorimer said slowly, flicking the tails of his coat as he sat down beside the psychologist.
‘Don’t you see?’ Solly smiled suddenly. ‘If this killer is a woman from the streets she is unlikely to be an addict. The unidentified hair sample suggests as much. Plus,’ he went on, ‘she must have obtained the gun from somewhere and knows how to use it.’
‘And she’s forensically aware,’ Lorimer pondered, following Solly’s line of thought now.
‘There’s something else,’ Solly went on then paused as though to gather his thoughts or, Lorimer suspected, to choose his words carefully. The policeman glanced sharply at his companion; he had a feeling that whatever Solly was going to tell him was not something he wanted to hear.
‘I’ve been going over this from different angles,’ he began.
‘Thinking out of the box, you might say,’ he added. ‘What have the three men in common apart from their cars and the way they were killed?’ he asked quietly.
Lorimer’s frown deepened. This was something he’d been over and over with other officers. ‘Nothing, so far as we know,’ he muttered.
‘Let’s say that the woman who picked Pattison up was a Glasgow prostitute. Just for argument’s sake,’ Solly said.
‘Okay.’
‘She gets into the cars after making some sort of proposition to each of these men, shall we say?’
‘Go on,’ Lorimer said, wondering