Author's note: I wanted to put Lestrade in the spotlight again, so enjoy!
He was aware that both Mycroft and Sherlock wished that the investigation was swiped under the rug; in fact, it already had been due to Mycroft's position.
But that wouldn't stop him. He had to know who shot Sherlock.
He was starting to think that he wouldn't like the answer. Sherlock had been acting strange – for him. Normally, he would have been after the culprit immediately. But he simply lay in his hospital bed, pretending not to know.
Definitely pretending. Greg had known him too long. Sherlock had been able to fool him in the past, but he had found him easier to read since he had returned, and there was a subtle change in his expression when he talked about the attack.
Sherlock was lying. There were several reasons why witnesses could be lying. One was fear, but Greg dismissed it without a thought. Sherlock didn't scare easy. There was blackmail, but how could someone have a hold over the brother of the British Government?
And then, of course, there was the possibility that he was protecting someone. A few years ago, Greg would have laughed, but Sherlock had given up two years of his life to make sure his friends were safe. Because that was what it ultimately had been about – not Sherlock himself, not Moriarty; but to save his friends. John had been furious that Sherlock had faked his death, but Greg hadn't. He had been relieved, joyful, but not angry. Sherlock was back and he wasn't responsible for his death, and it was enough.
But to hear afterwards that he had faked his death to take care of Moriarty's web – the unspoken Otherwise, it would have brought too much danger on those I care about hanging between them – had convinced the DI that Sherlock had become a good man, like he had predicted a long time ago.
The Sherlock Holmes who had disappeared for two years to get rid of a criminal mastermind's network would undoubtedly lie about who shot him if he felt he needed to protect someone.
But whom?
They had been breaking into the office of a rather well-known and important man; Greg was inclined to believe that Magnussen was more powerful that they had been told, simply because Sherlock was involved. So had he met someone his brother was connected with?
But Mycroft didn't need anyone to protect him. His position was untouchable; Sherlock didn't have to lie about who shot him even if it had been an associate of the British Government's.
This left someone Sherlock cared about personally, someone he knew intimately. Of course John had been there with him, but the idea was absurd. Their friendship hadn't been the same since Sherlock's return, but John would never harm him.
There weren't many others Sherlock cared for and who knew how to handle firearms, though – A wiry smile crossed his face as he considered that he was probably on the top of that list.
Then again, it was rather short. He had his suspicions, from certain allusions he'd overheard in the past, that Mrs. Hudson's past was rather interesting, but her shooting her boy was even more ridiculous than John doing it.
Molly? She was a pathologist, so she should know how to handle a weapon, if only theoretically. But again, why? And what should she be doing at Magnussen's office?
What if it wasn't one of Sherlock's friends that had shot him, but someone who was important to one of them.
Greg quickly couldn't think of a reason that one of his friends – most of them were Sherlock's too, anyway – would shoot Sherlock. The old ladies who took tea with Mrs. Hudson were rather difficult to picture as gun-wielding maniacs as well, and Molly – Tom maybe? But the break-up had been mutual, as far as he knew, and Tom had never shown any jealousy concerning his fiancée's long-standing crush.
But who –
Greg looked up from the file he was supposed to read when he noticed.
He had forgotten about one person.
Mary.
He didn't know much about John's wife, which was probably why he had overlooked her until now. She seemed normal and friendly, but nobody would think that John had been in a war at first glance.
In truth, he hadn't done his outmost to get to know her. John had slowly distanced himself from his friends since Sherlock had died; there had been no more drinks, no more dinners, and when Greg had checked up on him, he had always looked impatient and wanted him to be gone. The DI had accepted this as part of his grieving process and had been happy when he had heard from Mike Stamford (who was simply too nice to hang up on, which was why he kept the most in touch with John) that the doctor had found a girlfriend.
When he had eventually met her, though, it hadn't taken him long to admit to himself that he didn't like her.
He was certain the antipathy was mutual. It wasn't his fault, nor hers. Sometimes people simply didn't like each other.
It had caused him and the doctor to drift further apart. Once upon a time he would have considered him one of his closest friends. But he didn't blame him for it. A relationship changed things. So did marriage.
But the point was that he hadn't spoken over ten words to Mary since he had met her. It was difficult to imagine John being with someone who would shoot Sherlock. And she was pregnant, too. Why should she break into an office and try to kill her husband's best friend? It didn't make any sense.
Greg was convinced of this until he went to visit Sherlock and check up on his recovery and found John sitting in his old chair. Living at 221B. Not even mentioning his wife when Greg asked how he was doing.
He looked at Sherlock, but the consulting detective wasn't meeting his eyes.
So he talked of other things.
He couldn't speak in front of John. He might be wrong. He hoped he was wrong.
The doctor accompanied Sherlock to every crime scene again, so that it was some time before he and Sherlock were alone. The consulting detective had send John to talk to a witness – Greg didn't protest, he knew it would be useless – and was sitting in Greg's office, lost in his mind palace.
Until Greg shook him by the shoulder. Sherlock opened his eyes, clearly surprised. He hadn't touched him since the hug after his return.
Greg could have tried to be subtle about it, but at best Sherlock wouldn't understand at worst evade him, so he simply asked.
"Did Mary shoot you?"
Sherlock didn't answer. The silence stretched between them. Greg kept looking at him, showing him that he would not stop asking.
Finally, Sherlock said, "Yes."
"What?"
He was glad that it was already late and not many people were around; he had started shouting as soon as Sherlock's answer registered.
"Why? What in God's name could possess the wife of your best friend to – "
"It was necessary".
"Necessary?"
He couldn't understand how Sherlock could be so calm. He took a deep breath and willed himself to stop screaming, at least.
"How? Please explain".
"She shot me to save my life. The shot was perfect surgery..."
Greg couldn't say whether or not Sherlock believed what he was saying. If he did, he was afraid that the consulting detective had either been manipulated – given his intelligence, it was unlikely – or had suffered brain damage. For one simple reason.
"You died on the table" he said flatly, his voice betraying nothing of the horror he had felt when he and John had been informed of the fact in the hospital. "She killed you".
"I am alive" Sherlock said matter-of-factly.
"It was a close call".
Greg had sat next to John, trying to provide a comfort he needed himself. Molly had dropped by, as well as Mike Stamford; Mrs. Hudson had shown up with a thermos full with tea and tried to get them to drink it; Mycroft had sent an agent to watch over his brother and demanded hourly updates.
Come to think of it, Mary hadn't shown up at all until Sherlock had woken up. Greg hadn't paid attention then. It had been difficult to pay attention to anything.
"She had her reasons" Sherlock said with an air of finality. "It has already been brought to your attention that the case will not be followed up, Inspector. Please refrain from mentioning it again".
Greg winced. Not because of the threat – he didn't think Sherlock would allow him to come to harm – but because of the careless tone the consulting detective used. He hadn't spoken to him like this since he had come back.
John entered the room and Greg knew Sherlock had meant that he shouldn't tell him what he knew. It was for the best. After all, John had been forced to leave his pregnant wife. No one could live with someone who had shot their best friend.
He wondered what would happen. He wondered what John would decide to do – after all, she was carrying his child. Maybe he would decide to raise him or her on his own. He smiled briefly at the thought of a child at 221B. But soon enough, he shook his head, sighing. How could this have happened? How could John have chosen the one woman who would shoot his best friend?
It was a mess.
He knew that he couldn't prosecute, not with Sherlock and Mycroft being against it; but even if he had been able to, he wasn't sure whether he would have. She had shot Sherlock, had killed Sherlock – the doctors had called it a "miracle recovery" – but she was John's wife, and they were going to have a child together.
All he could do was try and be there for the doctor. And for Sherlock. It must be difficult to live together with this hanging over their heads.
He and John grew closer once more, commiserating over Sherlock's endangering himself, getting coffee while waiting for the consulting detective to finish his deductions.
It was almost like the last two years had never happened, but he knew better. He never told John he knew. But the knowledge was always there, in a corner of his mind, and sometimes, when he saw John look dejected, he felt the temptation to speak up. To talk about it. Because it was clear that Sherlock and John didn't.
But it wasn't his place. He had chosen to keep the identity of Sherlock's attacker secret instead of doing what he should have done; he had chosen to allow Mary to live her life, to let John make his decisions. He didn't have the right to force his friend's confidence.
He would have felt better, he decided, if he could have talked about it with someone. But John was out of the question, Sherlock didn't want to discuss the subject, and Mycroft undoubtedly shared his brother's opinion.
So he carried the secret around with him and ignored the urge to do something, anything, about it.
And then, shortly before Christmas, he was spending the evening at 221B once more and John told him, while Sherlock was experimenting, "We are spending Christmas at Sherlock's parents' house. Mary is coming to".
Greg looked into his eyes and what he saw shocked him.
John had always been easy to read.
He was going to forgive her. He was going to take her back.
Sherlock let something drop in the kitchen and picked it up, mumbling to himself. Greg's eyes went to the doorway and all he could hear were the words of the doctor in the hospital, his heart stopped.
Greg left early that evening.
He admitted to himself that he could not blame John for his life decisions. He had never had children. He couldn't imagine what the doctor had gone through.
But he also knew that he could never look at him in the same way again.
John called him at Christmas, no doubt to give him the season's greetings.
He didn't pick up.