How to humanely catch a mouse in my basement?

Well, there's this long skinny opening in our walkout basement wall and so far since we got our cats maybe like five mice have squeezed through the hole and then hid between two pieces of drywall in our basement until our cats find them... And when they do find them, it's really ugly, there's two of them so they fight over the mouse and like, rip it in half when it's still alive... I always feel so bad but the rest of my family seems to find it very entertaining... So today I went down to the basement and found my cats, both of them, staring intently at the drywall as if there were something on the other side. I instantly panicked and assumed it was a mouse, and took my cats upstairs, locking them out of the basement, then I went back and checked for myself, I lifted the two pieces of drywall apart and there was the little brown mouse, the dry wall is so tight together that the mouse can't even move and it's probably squishing the poor thing to death and when I opened it, it took the chance and ran for the opening, I freaked out and shut it again because I don't want the mouse loose in the basement, that would make it harder for me to catch it and let it outside. I called my mom and asked her what to do and she said to forget it, that the mouse had got in and now it was a goner and to just let the cats have it. But I feel so bad for the little guy, he's only a baby, he's SOOO tiny and really skinny cause he probably hasn't eaten since he came in our basement who knows how long ago. I really want to set it free before everyone gets home because if they know there's a mouse in our home, they'll be happy to watch it get shredded into ribbons. But I feel bad for the little baby and I want to free him so that doesn't have to happen. So, How can I trap him and let him out without getting bitten and without hurting him? My mom will know if I get bit, and she'd be furious cause that was her exact main reason for me not to help it.