Former Congress lawmaker, his wife and son were arrested on Wednesday after the burnt bodies of his daughter-in-law and three grandsons were found at his residence in Telangana, said reports.
The burnt bodies of Sarika and her three sons -- seven-year-old Abhinav, two-year-old twins Ayan and Sriyan -- were recovered on Wednesday morning from his Warangal home following a blaze.
Rajaiah, his wife Madhavi and son Anil were arrested after they underwent a police interrogation.
Sarika, who had allegedly attempted suicide in 2014, had also filed a dowry harassment against the trio and staged a protest outside Rajaiah's house along with her children.
Sarika's relatives had earlier expressed doubts about her death, claiming it could not be from a fire accident. They had also ruled out any possibility of suicide.
The 62-year-old parliamentarian, who had filed his nomination papers for the 21 November by-election to the Warangal Lok Sabha constituency on Monday, has opted out of the polls following the incident.
Former union minister of state Sarve Satyanarayana on Wednesday filed the nomination as the Congress party candidate for November 21 by-election to Warangal (SC) Lok Sabha constituency replacing.