BBC News reports that even before the Westgate shootout, al-Shabaab had been trying to use Twitter accounts to broadcast its message. However, notes the report, the accounts thought to be used by the group had already been shut down by Twitter twice in the past nine months. Each time, however, the account has re-appeared under a slightly different name. During the attack on Westgate, an al-Shabaab-linked account began putting out messages saying the attack was in retaliation for Kenyan forces' 'crimes' in Somalia and referring to 'fighting the Kenyan kuffar (infidels) inside their own turf', according to the report. Full BBC News report