Acans eating blue leg hermits?!

So yesterday i noticed one of my Acans i recently acquired with a dead blue leg crab stuck in his mouth region... okay took it as maybe the crab was dead and drifting around or something... Today i feed my fish and about 5 minutes later another one of my Acans has a dead hermit crab and its moving towards its mouth! Is this common? has anyone heard of this happening?

 

I've caught mine eating snails on a couple occasions. Wouldn't be too surprised about hermit crabs. Whether this is normal or not I couldn't tell ya!

 

Any chance what appeared as hermits were just hermit molts?

 

thats what i thought the first one could have been but the second time it happened just after i fed my tank, the crabs were going crazy on the sand bed. I did just add a bunch of new crabs. Im about75% sure they killed them.anyway, im still confused. Next time ill try and catch one in the act lol