Vikas alias Vikki alias Mahendra and Basant were arrested from a park near Alaknanda Ghaat in Haridwar, SP (city) D S Kunwar said.
They have confessed their crime during interrogation, he said.
However, three more persons accused in the case are still at large, the official said.
Pushpa Saklani, wife of senior lawyer O P Saklani, was found lying in a pool of blood at her home in the heart of the city on October 16 with her throat slit.
Vikas hails from Uttar Pradesh's Shahjehanpur district while Basant is a resident of Dehra Dun, the SP said.
Lawyers in the city had staged a bandh here on October 19 after the police had failed to meet their 24-hour deadline for the arrest of those who killed Pushpa.