I'm looking for solid police siren sources for a game I'm developing in unreal engine. I'm curious if I can use any of the assets posted on lcpdfr in my game legally or if there is a license against it somewhere I'm not seeing.

LCPDFR.com does not control the rights of other users' work, other than author's granting permission for us to host those works per our Terms of Service (which is necessary for the site to work).

 

Unless they have explicitly mentioned you can use it commercially, or have explicitly licensed it in a fashion where you could (for example, some open licenses), you should assume that the work is by default copyrighted by the owner, and you should contact them to establish whether they would like you to use their work in such fashion, and what terms they would set on that.