A total of 13 people have been arrested in connection with the shootout incident late on Sunday night at Ullal near here, city police Commissioner P S Harsha said on Monday.
Six people were arrested in connection with the firing, while seven others were held for assault.
The firearm used during the clashes has been recovered, he said.
The Commissioner said two groups of which one belonged to young political leader Suhail Khandak and their rival group in Ullal had clashed during the night.
Suhail fired six rounds of which one bullet pierced the leg of Irshad (18).
Irshad was taken to a hospital in Deralakatte, while Suhail and car driver Basheer, who were injured in attack by local people, have been admitted to a hospital in Thokkottu.
Preliminary investigation revealed that one Arshad, who was working with Suhail, had uploaded a WhatsApp status promoting the latter, which enraged Salman of Ullal, leader of the rival group in the same political party.
Salman questioned the WhatsApp campaign which triggered the incident, the Commissioner said.