LoadMainAssetAtPath always null

Inside Editor script, I’m using this to load existing texture from a folder:

Texture2D tex_r_df = (Texture2D)AssetDatabase.LoadMainAssetAtPath(“Assets/Zones/” + zoneName + “/” + “r_df”);

No matter what, the result is null. I’m absolutely positive, that path is correct. Any idea, where might be the catch?

Are you including the file’s extension?

Oh, uh, thank you. For some reason, I thought, extension is not needed for assets