  The entanglement swapping protocol is analyzed in a relativistic setting,
where shortly after the entanglement swapping is performed, a Bell violation
measurement is performed. From an observer in the laboratory frame, a Bell
violation is observed due to entanglement swapping taking place, but in a
moving frame the order of the measurements is reversed, and a Bell violation is
observed even though no entanglement is present. Although the measurement
results are identical, the wavefunctions for the two frames are different---
one is entangled and the other is not. Furthermore, for boosts in a
perpendicular direction, in the presence of decoherence, we show that a maximum
Bell violation can occur across non-simultaneous points in time. This is a
signature of entanglement that is spread across both space and time, showing
both the non-local and non-simultaneous feature of entanglement.
