ADJ at Gautam Buddha Nagar District Court, Deepa Jain sentenced Sonu, Monu and Kalu to 10 years jail term for killing their maternal grandfather Shiv Charan in June 2007.
The additional district judge also imposed a fine of Rs 25,000 on each of them.
Assistant District Government Council said on June 23, 2007, the trio threw Shiv Charan and his daughter-in-law Kamlesh from the roof of their house in Behlolpur village over property dispute.
Shiv Charan died while Kamlesh suffered critical injuries.