Of course, he was killed D:We don't know if Madara was killed and have little data even for speculations about his death.
The police force of Konoha didn't investigate mysterious deaths in their village- be it Madara or Minato. They didn't even pay attention to the ANBU and Biwako's deaths whose death should have arisen suspecions as they didn't died by Kyuubi's attack..
>_>
How else could he have been revived? xD