Dinesh Kumar, who hails from Bhiwani in Haryana and was at large for about a year, was apprehended from the Civil Lines area on Friday.
He was wanted by the Rajasthan Police in the murder case and was residing in Rohini to evade the arrest, S S Yadav, Additional Commissioner of Police (North), said.
Dinesh and the victim Bhiwani, both wrestlers, were serving in the BSF.
“Singh used to keep his family with him at the place of his posting. While their posting at Silchar in Assam in 2009, Dinesh got intimate with the wife of Singh and relation between the two friends got strained due to this.
“In May 2010, Dinesh along with his associates went to Taskola at the behest of the victim’s wife Meena Kanwar and shot dead Singh using his licensed rifle,” Yadav said.
The wife of the deceased and other co-accused were arrested for entering into criminal conspiracy to kill Singh but Dinesh was still at large.