  We present model independent measurements of the helicity basis form factors
in the decay D+ -> K- pi+ e+ nu_e obtained from about 2800 decays reconstructed
from a 281 pb^{-1} data sample collected at the psi(3770) center-of-mass energy
with the CLEO-c detector. We confirm the existence of a previously observed
spin-zero K- pi+ component interfering with the K*0bar amplitude. We see no
evidence for additional d- or f-wave contributions.
