  We study double ionization of He driven by a near-single-cycle laser pulse at
low intensities at 400 nm. Using a three-dimensional semiclassical model, we
identify the pathways that prevail non-sequential double ionization (NSDI). We
focus mostly on the delayed pathway, where one electron ionizes with a
time-delay after recollision. We have recently shown that the mechanism that
prevails the delayed pathway depends on intensity. For low intensities
slingshot-NSDI is the mechanism that prevails. Here, we identify the
differences in two-electron probability distributions of the prevailing NSDI
pathways. This allows us to identify properties of the two-electron escape and
thus gain significant insight into slingshot-NSDI. Interestingly, we find that
an observable fingerprint of slingshot-NSDI is the two electrons escaping with
large and roughly equal energies.
