On the street.

Ye Qiu used a tracking talisman to search for Master Mo's whereabouts.

Earlier at the Wang family, Ye Qiu had already harbored murderous intent. If he hadn't been concerned that Master Mo might have accomplices, he wouldn't have let him leave the Wang family at all.

Not to mention Ye Qiu's grudge against the Shaman God Sect, just the fact that Master Mo used Gu techniques to harm people was enough to warrant his death.