ok i understand and in Ontario Canada we do the same thing and when we do place flowers or candles at the grave sight the company who does maintenance on the property has the rights to remove items in order to cut the grass or just cause of issues broken / flowers are dead things like that so this could have happened not sure ..if everything else was still there then yea you are correct in assuming this happened..for us here in Canada our candles are about $1.00 each or less depending on what type you buy..
now you should let this go due to this is a minor thing and it could happen to anyone .. also a animal like a squirrel or bird could have taken it ..i had shinny rocks out side one year and i found them all over my yard and this was cause of a bird and the squirrels..