  We use circular dichroism (CD) in time- and angle-resolved photoemission
spectroscopy (trARPES) to measure the femtosecond charge dynamics in the
topological insulator (TI) Bi$_{2}$Te$_{3}$. We detect clear CD signatures from
topological surface states (TSS) and surface resonance (SR) states. In
time-resolved measurements, independently from the pump polarization or
intensity, the CD shows a dynamics which provides access to the unexplored
electronic evolution in unoccupied states of Bi$_{2}$Te$_{3}$. In particular,
we are able to disentangle the unpolarized electron dynamics in the bulk states
from the spin-textured TSS and SR states on the femtosecond timescale. Our
study demonstrates that photoexcitation mainly involves the bulk states and is
followed by sub-picosecond transport to the surface. This provides essential
details on intra- and interband scatterings in the relaxation process of TSS
and SR states. Our results reveal the significant role of SRs in the subtle
ultrafast interaction between bulk and surface states in TIs.
