District and Sessions Judge Amitabh Kumar convicted Rahul Singh, his wife Bharti Singh and their relative Seema Singh in the murder case of DVC executive engineer Ajay Singh and his wife Vandana Singh on September 4.
Another accused Amit Singh was also convicted and sentenced to three years imprisonment.
Bharti used to work as a maid at the residence of the victims.
According to the prosecution, Bharti and the other convicted persons looted ornaments from the house after murdering the couple.