Do you think they killed without evidence? That seems a bit strange, given that description! Although, killing without evidence makes more sense.
I think they wouldn't reveal such a strong role with evidence on the first turn of the Mafia game, so they probably didn't have any evidence. Besides, a turn without evidence bypasses all defenses, and Rudiy, as Arandor noted, was a player who might have been protected. I think the description is fine.
The killer immediately left the scene, and in the morning, when everything was over, nothing was found near the body...
Rudiy's murder is somewhat predictable, but also well-planned, because they knew he was often protected/healed, and therefore they used their ultimate ability. It seems the Mafia is aiming for a 100% victory.