The incident occurred near Thutangi village, about 125 km from coastal city of Visakhapatnam.
K Sarveswara Rao, belonging to Telugu Desam Party (TDP), was representing Araku constituency in the Andhra Pradesh state Assembly.
The Maoists attacked Rao and former MLA Siveri Soma when they were attending a programme in Araku.
They were shot from point blank range. A large number of Maoists allegedly participated in the attack.
Rao was elected from Araku, a constituency reserved for the Scheduled Tribes, on YSR Congress Party ticket in the 2014 elections, defeating Soma of the TDP.
In 2016, Rao switched loyalties to TDP.
According to the police, both Rao and Soma had received threats from Maoists in the past.