A 35-year-old mason allegedly poisoned his three sons before swallowing it himself due to alleged strained relations with his wife in Yellendu town around midnight on Friday.

The mason and his two sons died at a hospital in Khammam on Saturday morning. His youngest son is battling for life at a private hospital in the district headquarters. According to police sources, N. Samba Murthy, a mason of Station Basti locality in Yellendu, allegedly administered a soft drink laced with poison to his three sons -- Sanjay, 10, Manikanta, 7, and Kaleshwar alias Nani, 4, before consuming the same at his house late on Friday night. Samba Murthy, Sanjay and Manikanta died while undergoing treatment at a hospital a few hours later. Kaleshwar’s condition is stated to be serious. Samba Murthy’s wife allegedly left home leaving behind her three sons a few weeks ago following a tiff with him. The Yellendu town police registered a case and are investigating.