TIFU by accidentaly stealing the keys of a friend and now looking like a creep

I(M) have (or rather had)a good friend (F) I met a couple months ago. We got along really well, hung out a lot, and shared a pretty tight friend group.

A few weeks ago our group went on a short trip to an event. We stayed in one big hotel room from Monday to Thursday. Everything was normal, we had fun, and then everyone went home.

At some point after the trip, this friend apparently mentioned multiple times that she had lost her house keys during the trip. The problem is that I have absolutely no recollection of her saying this. Either I wasn’t paying attention or I somehow just forgot. That same week I went to visit my sister for a night (on a Weekend), and right after that I visited my parents. I live pretty far away from both of them, so this was a bit of a trip.

While I was at my parents place, I noticed a random key in the pocket of the jacket I always wear. I pretty much use the same jacket every day, mostly out of laziness. My first thought was that the key might belong to my parents. I had already been there for hours when I noticed it, so I asked my dad. He said it wasn’t his. I didn’t bother asking my mom because she’s extremely unreliable with stuff like that and usually has no idea which keys belong to what.

The key was attached to a broken key ring. Because of that, I assumed it might have broken off my own keychain. I have a bunch of random keys from when I took over my brother’s old rental apartment, and even he doesn’t know what half of those keys are for. So my working theory became: “Okay, this must be one of my random keys that broke off.” Since I didn’t have another key ring at the time, I just hung the key on a hook in my apartment and figured I’d ask my brother or his wife the next time I saw them if it belonged to them. Fast forward to a couple days ago. I invited some friends over to my place. Among them was the friend who had lost her key.

At some point she noticed the key hanging on the hook.

She immediately got excited because she had apparently been searching for it everywhere. I basically just said something like, “Oh, so that was your key,” and that was the end of the conversation for that night.

A couple days later she messaged me privately asking why I had her key.

I explained exactly what happened: that I must have accidentally taken it during the trip, that I found it in my jacket later, and that I assumed it belonged to my family or one of my own random keys.

She didn’t reply for a while. I thought nothing off of it and a couple days later, when I asked if she wanted to hang out again, she told me she thought the whole situation was really creepy. According to her, the story didn’t make sense because she had repeatedly told everyone that she lost her key. She also said that I’m very attentive and remember things people say, and apparently all of our friends she asked agreed that it’s strange that I wouldn’t notice something like that (nice compliment I guess 😭)

That’s when it hit me how bad this looks from the outside. From her perspective: -I apparently somehow took her key from the hotel room without noticing it wasn't mine.

-It sat in the pocket of the jacket I wear almost every day from Thursday until the weekend, and I didn’t notice it.

-Despite her talking multiple times about losing her key, I never connected the dots.

-When I found the key, I only asked my family about it and none of my friends.

To make things worse, I even briefly thought about sending a picture of the key to my brother and his wife to ask if it was theirs. Then I decided not to, because my brother visits me sometimes anyway. If I had done that, I would at least have some proof that I genuinely thought the key belonged to someone else.

Instead, all she sees is: I had her house key for weeks and only casually revealed it when she came to my apartment and not by choice. When she told me it felt creepy and that my story didn’t add up, I basically responded:"Yeah… that’s completely understandable. I’m sorry I don’t have a better explanation, but I swear that’s exactly what happened. I get why it looks weird, and honestly I’m not sure I’d believe myself either if I were you. Thanks for being honest. I’ll leave you alone in the future.”

Now I’m sitting here thinking: what the hell just happened. At one point I almost left the key at my parents place because I thought it might belong to them. If I had done that, none of this would have happened. Instead, it looks like I secretly held onto my friend’s house key for weeks, and now there’s a good chance I’ve lost not just that friendship but possibly most of our shared friend group too. All because of a key I apparently picked up without realizing it and I have no idea what to do now....

TL;DR: Accidentally took my friend’s house key during a group trip without realizing it. Weeks later she found it hanging in my apartment . Because she had mentioned losing it multiple times (which I somehow don’t remember) and I never asked any friends about the random key I found, my explanation sounded suspicious and creepy. Now she thinks I secretly had her key the whole time and I may have ruined the friendship and possibly my friend group.