RBBM I have been wondering about this myself. I thought the ring camera that caught M & K arriving home at 1:56 or thereabouts showed them walking up to the house after being dropped off. If so, why wouldn’t it also catch X and E arriving home?
Is it possible that M & K were not seen on camera going up to the house? We believe LE knows who the “private driver” was that dropped them off. They took his/her statement that he picked them up near the food truck, drove them home, dropped them off, and drove away. LE obtained video that corroborated his story. The ring footage may have caught the vehicle just around the corner coming and going, maybe at the corner of King and Queen.
If X & E walked home from Sigma Chi, they probably crossed Taylor Ave and used the stairs between the two buildings across from their house. I don’t think that would show up on that ring camera. It also wouldn’t show if anyone was with them. This still doesn’t explain the missing hours, only the possible reason why M&K were seen, but X&E were not.