"You know," said Richard, surveying the group of people assembled in one of the interview rooms, "there have been quite a few similarities between this case and the one that I was originally sent to the Caribbean to solve. To start with, a police officer was murdered – and in a seemingly impossible way. If I had learned the lessons from the past, I would have solved this case much more easily."

As well as the team, Bernard Taylor and Jules Perrot were present at the meeting, at Richard's express invitation.

"So does that mean that you know who killed Hannah?" asked Brad eagerly.

"Oh yes. Hannah was killed by the only person who had the means, the motive and the opportunity."

"But how did the killer manage to avoid being caught on the CCTV, Chief?"

"He didn't. Look …" Richard nodded to Camille, who played the footage from the murder scene, starting with Hannah's arrival in her car. "You see?"

"But … but … there's nothing until André arrives in his car!"

"Exactly. And that is the point. Hannah was alive until that very moment. You killed her, André, didn't you?"

Brad and Gino gasped in disbelief. André gave a short laugh. "Me? That's perfectly ridiculous."

"That's a very serious allegation you have made, Inspector. I trust you can prove it?" Bernard Taylor's voice was sharp and held just a hint of menace.

"Yes, sir, I believe I can."

"But why on earth would I want to kill Hannah?"

"To stop her revealing your dirty little secret – that you have been leaking confidential information about Interpol inquiries and that you are, in effect, in the pay of a bunch of gangsters."

"Go on, Inspector." Bernard Taylor was suddenly very interested indeed.

"You have been lying to us from the very beginning, André, and have done your best to throw us off the scent. And it almost worked. Had it not been for the PJ deciding to place an undercover officer in the casino" – he indicated Camille – "we might never have cracked the case at all.

You told us that Hannah had no boyfriend. We now know that was a lie – you were having an affair with her. You may have thought that your visits to her apartment went unnoticed because you never went in, but you didn't bargain for Madame Desfarges, the concierge, and her interest in footwear."

"Those are very smart shoes" interjected Camille. "What are they - Hugo Boss? Magnanni? Paul Smith?"

André looked bewildered. "You see, the concierge only has a very narrow window onto the street, so she tends to be very interested in what people wear on their feet. She told us the man who visited Hannah at least once a week wore nice shoes."

André shrugged. "So? Thousands of men have shoes like these."

"I don't think so, not at that price tag" said Richard drily. "But no matter – let us continue. We tracked you to your little love nest – a hotel near the ring road, one of the Ibis chain. A pretty anonymous place, but the receptionist had no difficulty in recognising Monsieur and Madame Lavalle from the photographs we showed her."

André saw it was pointless to deny it. "OK, so we were having an affair – that's not a crime, is it?"

"Fortunately not, or we would be forced to arrest a significant proportion of the population. You went to some considerable trouble to keep your relationship a secret from everyone, and it was really just bad luck that Hannah decided to check out the casino on the very day you called in for your latest payoff. We have it all on CCTV. Camille, if you would …?"

Camille ran the footage and all eyes turned to the screen. "You see, here is Hannah on her way to the casino. Then she stops suddenly – she has caught sight of someone she knows. And there you are – the man in the baseball cap. She calls your name but it's noisy and you don't hear so she crosses the road and follows you. And then you disappear down this alleyway."

Camille took up the story. "The side entrance to the casino is down that alleyway. Well, you would know that as I expect you had been there many times already. You made your way to the Manager's office. And Hannah followed you. How do we know this? Because I was working there under cover and I saw her in the corridor. She had obviously been listening to the conversation you were having with Carlos. What were you doing? Giving tip-offs? Collecting money? Whatever it was, it was enough to make her realise that you were the source of all the leaks that had kept the gang one step ahead of Interpol and the national police forces. I saw her face when she came back up the corridor towards me, and it was the face of someone in deep shock."

"So here is Hannah reappearing from the alleyway" Richard continued. "She is clearly upset and trying to get away as quickly as possible. And a few minutes later, here you are again, waiting for a taxi. Now your phone rings, and you take a call."

Camille froze the screen. "Now take a look at the time. 8.23 pm – the exact time that Hannah called André to set up a meeting."

"Pure coincidence. You can't prove that the man in the baseball cap is me. And you are forgetting we have already established that Hannah was responsible for the leaks. You remember the safety deposit box?"

"Ah yes. The safety deposit box. That was really very clever. You knew I was a tea-drinker so it was likely I would at some point use the tea caddy in Hannah's apartment. It was you who gave me the key the day I arrived, so it would have been easy to get a copy made, and let yourself in one day when the concierge was out. And then, if I recall correctly, it was you who suggested it was a locker key and you who so helpfully offered to search for the depository and you who 'found' the only evidence which incriminated Hannah. But you see Camille and I have just been to visit that bank – and do you know, that deposit box was only opened two days ago, after Hannah's death. The clerk told us it was opened by a man on behalf of his mother and he too had no difficulty in recognising your photo. So you see, the game is up, André."

Lieutenant Sorel bit his lip.

"The only thing we haven't found is the gun. It's a common make and we've checked – you do have a licence. My guess is it's hidden in plain sight – you wouldn't want to keep it at home in case your wife or children found it. My guess is that it's here on the premises somewhere. Gino: would you be kind enough to search the Lieutenant's desk and locker, please?"

Gino nodded curtly and left the room.

"Did you intend to kill Hannah? Maybe not: perhaps you tried to pretend you were only acting as a decoy. Perhaps you tried to persuade her that you were doing it so the pair of you could start a new life together somewhere exotic …? But Hannah was smart – a good copper is how you described her – and she was having none of it, was she? You knew she would report you so you had to kill her. And you very nearly got away with it."

André decided to brazen it out. "Well, good luck with getting a conviction. It's all circumstantial, you haven't a shred of real evidence."

Gino came back into the room, grim-faced. He was carrying an evidence bag.

"No? Well, if that gun that Gino has just found turns out to be the one that killed Hannah, that's not going to look good for you, is it?"

He turned to Jules Perrot, who was looking rather shaken. "Jules, neither I nor any Interpol officer has any powers of arrest here, so would you do the honours, please?"

As Lieutenant Sorel was being led away, Brad caught his arm. "You killed Hannah – our colleague and friend – for money, for sheer greed?"

André shook off his hand and shrugged resignedly. "I could never earn enough for Nathalie to spend", he said simply.

"So this is all because you couldn't control your wife's extravagance?" Gino was contemptuous. "And I really liked and respected you. Just goes to show what a good judge of character I am!"

Once Jules had taken André away an uneasy silence settled over the room. Bernard Taylor returned to his office. Gino and Brad looked decidedly white and shaken. Richard fidgeted, uncertain of what to say.

"I really hate it when a police officer turns bad" he muttered to Camille. "It leaves such a nasty taste."

"Especially when he seemed such a nice man. It just goes to show: you can never tell what someone is really like from outward appearances." He shot her a quick glance, but she had transferred her attention to the junior members of the team. "Are you OK?" she asked Brad, rubbing his arm sympathetically. You've just had a big shock."

"Yes, thank you, Major. I was just thinking about poor Hannah – you know, finding out that the man she loved was a traitor and then being killed by him. She was such a good friend and colleague – she didn't deserve that."

"I'm sorry not to have had the chance of meeting her", said Richard. "She sounds like someone worth knowing – even if she did name her cat Patterson!"

"What's wrong with that, Sir?" asked Brad, glad to be diverted onto a lighter topic.

"It's just that the Commissioner of Police on Saint-Marie was called Patterson – and he was the Inspector's nemesis and personal bête noire!"

"Well I admit it's a bit of an unusual name for a cat, but perhaps Hannah was a fan of American thriller writers?" suggested Brad.

"Or it's as the concierge says, a play of words on patte."

"Mind you", added Gino thoughtfully, "Hannah did once tell me when she had had a bit too much to drink that years ago when she was very young she had a bit of a fling with a police officer when she was on holiday in the Caribbean!"

Richard and Camille looked at each other, appalled.

"It couldn't be …"

"No, of course not, it's a common name …"

"But still …"

A slow smile spread over Richard's face. Of course it was extremely improbable, but in the unlikely event that he came across Selwyn Patterson again he would be sure to drop Hannah's name into the conversation, just – you know - to be sure …

A shrill ringing interrupted his reverie. Brad grabbed his phone.

"Oh my God … the baby … it's coming!"

"Well, what are you waiting for – get over to the hospital. Go!"

Gino sprang into life. "Come on, I've got my bike outside, I'll take you!" The two rushed out, leaving Richard idly wondering if Gino's bike had a sidecar.

"No, it doesn't" said Camille, reading his thoughts. "It would be madness in the Paris traffic! But Brad can ride pillion."

"Well," said Richard rather wearily, "I suppose we had better complete the paperwork on the case." He sat down at his computer and started to key in the relevant details. A few minutes later, the door opened and Bernard Taylor re-appeared.

"I see Gino and Brad are on maternity duty" he said good-humouredly, "which gives me the opportunity for a private word with you both." He perched on the edge of a desk, and shook his head sadly. "This is a bad business, Inspector, there's no point in denying that. But thanks to you we have solved two crimes and I'm very grateful. Your Super back in London was quite right – he said you were the man for the job."

Richard's heart swelled with pride; in his experience praise from above was rare. "Well, that's very kind of you, Sir, and I'm sorry that the outcome turned out to be such a distressing one for the Department. But it was a team effort – I couldn't have done it without Camille – er, Major Bordey – and Brad and Gino were also invaluable."

"Yes, well I have already commended Major Bordey to the PJ for her excellent work on this case. And now I suppose you will want to be off home back to London. I will get my PA to make the travel arrangements for you."

For some reason Richard found himself surprised. "You mean … I am free to go?"

"Yes of course, dear boy, once you've completed the paperwork."

"You haven't been speaking to Chief Superintendent Hewitt in London, then?"

"No, of course not. I must say, I am a little puzzled. Did you expect me to?"

"Oh no, Sir. It's just that … well, when I went to Saint-Marie it was supposed to be just for the one case but then the Commissioner and my boss at the Met got together and told me I had to stay."

"Well, I can assure you, Inspector, that whatever may have happened in the Caribbean I wouldn't dream of keeping you here against your will. I am no macchiavellian manipulator! Of course the team is now lacking a leader, and if you wanted to stay I would be delighted to have you. Actually, from what I have seen of your work I think Interpol would suit you very well, but it is entirely your decision."

He turned to Camille. "And you, Major Bordey, now that we have lost Sergeant Morris there is a place for you too on the team if you are interested."

Camille nodded, and glanced at Richard who was clearly struggling to control his reactions.

"Well … er … it's very … um … flattering, Sir, and Interpol does sound an attractive place to work, but I think I really need to go home."

"That's a pity, Inspector, but of course I quite understand. I believe this is your first trip to Paris? Well, you have hardly had time to see much of our beautiful city – and believe me there is much to see. May I suggest that you take tomorrow as a day off and go and view some of the sights – I am sure Major Bordey would be happy to show you around – and then we will organise your homeward travel for the following day. And of course if you should change your mind in the meantime, just let me know!"

He shook Richard firmly by the hand and wished him a safe journey, then returned to his office. Richard turned to Camille with a feeling of wonder.

"I can't believe it, I really am going home!"