Dehri police inspector Sanjeet Kumar Sinha said the incident occured on NH 2 near Patnawa village in the district.
The 25-year old trainee police constable was travelling on a motorcycle from Dehri Bihar Military Police camp to Indrapuri with his two colleagues when their bike dashed against a tree that had fallen on the NH.
All the three men were rushed to Dehri for treatment, where the trainee constable, a resident of Nawada died. The condition of the two injured is critical.