  A search for the decay of neutral, weakly interacting, long-lived particles
using data collected by the ATLAS detector at the LHC is presented. This
analysis uses the full dataset recorded in 2012: 20.3 fb$^{-1}$ of
proton--proton collision data at $\sqrt{s} = 8$ TeV. The search employs
techniques for reconstructing decay vertices of long-lived particles decaying
to jets in the inner tracking detector and muon spectrometer. Signal events
require at least two reconstructed vertices. No significant excess of events
over the expected background is found, and limits as a function of proper
lifetime are reported for the decay of the Higgs boson and other scalar bosons
to long-lived particles and for Hidden Valley $Z^\prime$ and Stealth SUSY
benchmark models. The first search results for displaced decays in $Z^\prime$
and Stealth SUSY models are presented. The upper bounds of the excluded proper
lifetimes are the most stringent to date.
