Bassiri, who had abandoned Zemla before violence erupted, was informed of the events. He was offered to escape to Mauritania by car, but he refused it. According to Salem Lebser, he replied: "Nobody could say I'm an adventurer who has led people to death and then disappeared..I already fled once Morocco, where I felt like a stranger. But I would not fled from my own land". Bassiri was tracked down that night, detained around 03:00 AM of June 18, and jailed at El Aaiun Territorial Police headquarters. On June 19, and after being allegedly tortured, he testified before the Spanish military authorities. A photograph of him registering before the "Habs Shargui" prison authorities is the last known trace of him. Later, he was allegedly moved to "Sidi Buya", the Spanish Legion headquarters in El Aaiun. According to testimonies given by three different persons to then apostolic prefect to Spanish Sahara Félix Erviti Barcelona, Bassiri was executed by a Spanish Legion patrol in the dunes surrounding El Aaiun on the night of 29 July 1970, although Spanish authorities of the time claimed that he had been expelled from the territory to Morocco on that date, moreover they also claimed later that Bassiri had entered Spanish Sahara illegally from Algeria in September 1970. Spanish colonial authorities even claimed in 1971 that Bassiri had died on the Skhirat coup d'état against Hassan II.