Akali Dal general secretary Ranjit Singh Rana was arrested along with two other suspects a day after he allegedly murdered a Punjab Police assistant sub-inspector in full public view.
Police also recovered the black SUV in which he fled after the murder of ASI Ravinder Pal Singh.
Three weapons have been seized from him - including a .315-bore rifle of Rana that police said was the murder weapon. Singh was killed while trying to protect his daughter from harassment by the accused.
Rana was arrested from Rajoke village in Tarn Taran district. The two others arrested were Dharamveer Singh, who allegedly accompanied Rana to the crime scene, and Prabhjit Singh.
Prabhjit was booked for sheltering Rana and also under the Arms Act.
Two other suspects, Sandeep, alias Sunny, and Gurbir Singh, alias Beera, are absconding.
Director general of police Sumedh Saini said, "This was a very serious incident and our primary duty was to nab the men who shot down our colleague."
He said two IGs, one DIG, five SSPs and about 1,000 cops were rushed to Tarn Taran, where the accused was hiding.
"Police parties went to Sohal village where the accused was hiding at the home of Prabhjit, alias Sandy. As the police party approached, Rana opened fire at them and fled."
The SHO of Chehhertta police station, under which the crime scene falls, was sacked following the incident.
Later, the accused were spotted near Basrake village but managed to flee from there as well. Finally, Rana was cornered in the border village of Rajoke, near Khalra, and arrested.