I'm not entirely sure, but it could be possible. They are much bigger and can be more aggressive, especially during feeding times. I've heard that Red-Claw shrimp like to chase Snowball shrimplets around, probably would eat them too if they do catch them.
If your glass shrimp = ghost shrimp, then it's well-known that Ghost shrimp will consider smaller shrimp prey and shouldn't be kept with smaller shrimp if you want to maintain their population.
I'd suggest moving the glass shrimp to another tank or feeding them to something larger (a nice puffer perhaps?). Ghost/Glass shrimp are pretty aggressive and overfeeding will likely not compensate to prevent the easy predation of your RCS.
Actually that suggestion that it might be a juvenile Red Claw Macro is a good one to consider. If it is in fact a Macrobrachium species, you really need to separate them immediately b/c your RCS will be gone.
I wanted to thank you all for your input. Researching this i have concluded that the shrimp is infact Palaemonetes paludosus. Thank goodness not the redclaw although predation by this species is common as invert1 noted. I believe this was just scaveging by this species (rasetsu noted) but will keep a close eye. My current RCS population is 20+ strong with 3 berried shrimp now. Additionally the tank is heavily planted with mats of glosso and Dwarf baby tears so cover may help. Thanks