According to police, the duo has been arrested from north west Delhi's Narela area.
"Gurjeet Kaur, whose husband is in Dubai, eloped with Ajay Kumar and took along with herself her son Harmanpreet Singh. The child was beaten to death and thrown away from a train near Katra railway station in Jammu and Kashmir in January, said a senior police officer.
"The body of the child was found by Katra GRP personnel. Katra police contacted Narela police station in west Delhi giving information that the location of the accused was traced to the area.
During questioning, the woman, who confessed to killing her own son, saying she had "no affection" for him, told police that her husband has not returned from Dubai and had asked her to live her life the way she wanted.
