>>> u.s. officials confirm that authorities in tunisia have arrested a man possibly connected to the deadly attack in benghazi last month. and tonight, more e-mails about the attack are making news. our report from chief correspondent andrea mitchell .

>> reporter: as a possible suspect for the benghazi attack was being questioned, critics disclosed e-mails obtained by nbc news. the first alert read, embassy tripoli reports approximately 25 people, fired shots, explosions heard as well. ambassador stevens and four embassy personnel are in the compound safe haven. it said a friendly militia was helping to fight off the attack. soon, another said it was over. the fighting in benghazi has stopped, the compound cleared. on ground, attempting to locate personnel. later, a known terror group was said to be linked. nbc tripoli reports the group claimed responsibility on facebook and twitter and has called for an attack on nbc tripoli . they denied they were involved, causing more confusion.

>> you know, posting something on facebook is not in and of itself evidence, and i think it just underscores how fluid the reporting was at the time and continues for sometime to be.

>> reporter: shortly before midnight on 911, another e-mail reported that the assault on benghazi had escalated. the current shelter is under attack by mortar fire , today, the white house and state department says there were hundreds and even thousands of reports that night, and in the following days. all had to be analyzed. today, siecretary clinton appealed for patience on benghazi , but the white house knows that any detail can become a new source of criticism. andrea mitchell , nbc news, washington.