  Context: A variety of formation models for dwarf spheroidal (dSph) galaxies
have been proposed in the literature, but generally they have not been
quantitatively compared with observations. Aims: We search for chemodynamical
patterns in our observational data set and compare the results with mock
galaxies consisting of pure random motions, and simulated dwarfs formed via the
dissolving star cluster and tidal stirring models. Methods: We made use of a
new spectroscopic data set for the Milky Way dSph Leo I, combining 288 stars
observed with Magellan/IMACS and existing Keck/DEIMOS data, to provide velocity
and metallicity measurements for 953 Leo I member stars. We used a specially
developed algorithm called Beacon to detect chemo-kinematical patterns in the
observed and simulated data. Results: After analysing the Leo I data, we report
the detection of 14 candidate streams of stars that may have originated in
disrupted star clusters. The angular momentum vectors of these streams are
randomly oriented, consistent with the lack of rotation in Leo I. These results
are consistent with the predictions of the dissolving cluster model. In
contrast, we find fewer candidate stream signals in mock data sets that lack
coherent motions ~99% of the time. The chemodynamical analysis of the tidal
stirring simulation produces streams that share a common orientation of their
angular momenta, which is inconsistent with the Leo I data. Conclusions: Even
though it is very difficult to distinguish which of the detected streams are
real and which are only noise, we can be certain that there are more streams
detected in the observational data of Leo I than expected in pure random data.
