But (without observing the turn) they (schemed to slaughter the she-camel and) called their comrade (one of the nine ring-leaders); and so he ventured (upon the evil deed), and slaughtered her cruelly
Thereupon they called their comrade who seized her (- the she-camel) quite unlawfully with the help of others and hamstrung (her, and they were then overtaken by a calamity)
They called out to their friends. They took their share and then savagely hamstrung her!
Al-muntakhab fi tafsir al-Qur'an al-Karim
They called upon the leader whose heart was confederate with his hand; which held the knife and disabled the she-camel by cutting her hamstring muscles