All of my companions are lost (I don't know why). How can i find them?

[KaiserAta]

All of my companions are gone and i don't know how to get them back.There's no option to ask about the companions to the guy on taverns.And they said nothing before they were gone missing.
At some point of the game,my troop's mood was terrible.I think that's where i lost some Lady from Mormont (cant remember her name) and Barristan Selmy

I lost Thoros Of Myr when I was ambushed at Essos

I lost Bronn randomly

[boatswaiN]

They might be imprisoned when you defeated

[KaiserAta]

They might be imprisoned when you defeated

I wasn't defeated when i lost Selmy and Bronn.I'm sure of that.I only lost Thoros in a battle (which i won,but he fell unconscious)

[Vladyvid]

In taverns there are people who can tell you where you can find your companions if they leave your party. You have to visit taverns and ask around.