The accused, identified as Amjad was arrested here yesterday, said SSP Manila Patidar.
Amjad has confessed that he shot at the couple with the intention of robbing them. Another accused in the case remains absconding.
The manager of a Chennai-based company, Aditya and his wife were shot at by unidentified men on June 17 while they were going on their motorcycle from Haridwar to Delhi.
Aditya succumbed to his injuries at a hospital on June 23. His wife Vijaya Lakshmi also sustained injuries.