Event organiser D Radhika and her driver M Damodar, were nabbed during vehicle checking near ECIL crossroad.
During interrogation, they confessed to murdering 90-year-old K Venkata Laxmi Narasimha Rao on February 17, Additional DCP (Crime), Cyberabad, G Janaki Sharmila told reporters.
They also confessed to involvement in two more cases of house thefts under Musheerabad and SR Nagar police stations limits.
Police recovered 28 tolas of gold, three kg of silver ornaments and electronic goods, all worth Rs 25 lakh, which were sold after the theft, the official said.
On Feburary 17, they entered Narasimha Rao's house, a distant relative of Radhika.
When he raised an alarm, Damodar pounced on the old man and strangled him with a towel, resulting in his death. Later, Radhika took the gold and silver ornaments after which they decamped with the booty, the police said.