^Adding to that.
You should understand why the phone is almost untraceable.
The phone is off, no worries, the cyber police can still locate it using some advanced tools but since the battery is dead, the phone can't send, reply to any kind of signal, so it really can't be tracked.
I know you'll hate it, but stress your brain, relax, have a coffee, you might get the place you placed it last.
Hope this help.
All the luck.