The picture does not jibe with your description. That would fit quite easily under the T-shirt. Unless the problem was the necklace, not the crucifix -- that the beading was in colors or in a color pattern that the principal thought was "gang-related."
The pic I saw was close up so I had a different perception.
The pic tonight is even closer.
But you are right it is longer.
Don’t ask me what the murderer was wearing for sure.