The accused, identified as Karamveer, allegedly killed Jogesh Kumar yesterday suspecting him of instigating the latter's daughter to file a domestic violence case against him (Karamveer), they said.
The accused got married to Kumar's daughter Preeti in 2016. After the marriage, she learnt that he was addicted to alcohol, police said.
He allegedly used to harass her. Preeti later filed complaints of domestic violence with the police as well as in Dwarka court, they added.
A mediation centre at the court was hearing the complaint and yesterday was the third hearing.
The accused told police that his father-in-law used to interfere in his marital life and he felt that it was because of Kumar that his wife was staying away from him, the police said.
The deceased worked at a government school in the Tagore Garden area here.