Flashbulb memories (FBMs) are consistent recollections of specific details of the reception context of events. Four theoretical models accounting for FBM formation (Brown & Kulik, 1977; Conway et al., 1994; Er, 2003; Finkenauer et al., 1998) were tested on average 21 and 524 days after the 9/11 attacks in the US in 2001 in two groups of participants (US, N=112; non-US, N=727). Structural equation modelling revealed that (1) a revision of Finkenauer et al.'s (1998) model provided the best fit indices in both the US and non-US groups, (2) several relations among latent variables that were predicted by the three other models (Brown & Kulik, 1977; Conway et al., 1994; Er, 2003) were not significant, (3) with respect to Finkenauer et al's model, the "direct path" (from novelty/surprise to FBMs) was found to be significant only for the US group, while the "indirect path" (from emotional states, rehearsal and event-memory to FBMs) was only significant for the non-US group. It is suggested that the specific activation of social identity in the US group can explain these differences.