Two minor girls were killed and another fell seriously ill when their stepmother poisoned them at Baltara village in Bihar's Khagaria district, police said.
Paura police station in-charge Ram Nath Soren said that Runa Devi, the step mother of the girls - Lakshmi (6), Sarswati (8) and Sweta (2) - had mixed pesticide in their meal last night following a quarrel with the girls' mother.
While Lakshmi and Saraswati died within hours of eating meal, Sweta was rushed to a nearby hospital where her condition was stated to be critical, he said.
The stepmother later confessed and was arrested, Soren said.
The bodies of the girls have been sent for post mortem.
Their father Gutti Lal, who works in New Delhi, has been informed, Soren said.