Two siblings, who were at home in Ramnagar of Seraikela Police station in Seraikela-Kharswan district, died when lightning struck their thatched house during rains.
The two were identified as Shivcharan Lohar (27) and Chotu Lohar (22).
A tree adjacent their house was also burnt.
In another incident, a 64-year-old farmer died when he was struck by lightning in Banai village under Rania police station of Khunti district.
The victim Ram Narayan Sao was ploughing his field when the incident occurred, police said.
Two cattle also died in the incident.