I thought about this but never asked this before: Have other images of Annie Le entering the Amistad building been released? Is it unusual that they wouldn't show the full video, just a snap shot? Maybe there were people on the video, for instance, who could have been key to Annie's disappearance at the time. Plus, there was never any speculation as to what she was carrying, which could have been important to find her whereabouts or her last known location after her card scan.
(update) Okay, I was able to find a wider angled image of Annie Le from that surveillance footage. It was on a news report posted on youtube. Was it ever mentioned if the image was taken on the ground floor or in the lab area? The image seems to show her carrying items Ray Clark said he saw her leaving with around 12:30pm when he said he last saw her: a notebook and two bags of mouse food.
Here's another one I found on myfoxny.com in a video story
http://www.myfoxny.com/dpp/news/local_news/connecticut/090914_Yale_Students_Body_Identified