The deceased have been identified as 28-year-old Rajwinder Kaur and her son Tejdeep, Superintendent of Police (SP) Jagjit Singh Saroya said.
The accused, Jaspal Singh, fled after murdering his wife and son last night.
Singh had returned from Manila about six months ago and there was a family dispute over his alleged second marriage there, Saroya said, adding the dispute in the family is believed to be reason behind both the murders.
No arrest has been made in this case, the SP said, adding police parties have been sent to different places to arrest Jaspal.