Bugs. feces. pebbles.?

last week i found in my bathroom, inside my braces box, a strange bug who i am pretty sure it had left his feces, since i found a strange brownish looking pebble inside the box. today i found another one pebble-like thing next to my window. i want to know what bug is it. i don't see any bugs in the house, i don't know if its a roach but i looked for images on line and their feces look a little bit longer than the ones i saw. those feces are hard when you touch them and crumble when you squeeze it with your nails. can you please help me identify? the bug looked a little oval and long. with lines on his back, like roaches but i am not sure... please help!!