ZAHAR, Tunisia (AFP) - Jabeur Khachnaoui, one of Tunisia's Bardo museum assailants, was months away from graduating from high school when he abruptly left home and went to Libya, a relative told AFP Friday.

Jabeur, who was killed by security forces after Wednesday's massacre in which 21 people died, mostly tourists, was pious and a loner who never gave his parents a hard time, said the relative who declined to be identified.

Prime Minister Habib Essid, hours after the attack, identified one of the two attackers killed in the capital Tunis as Hatem Khachnaoui.

But police sources in his home village of Ibrahim Zahar in south-west Tunisia said his first name was in fact Jabeur.

He was born in 1994 in the village of Ibrahim Zahar in the impoverished Kasserine region near the border with Algeria.

Kasserine is at the foot of Mount Chaambi, where security forces have been hunting militants since 2012.

His father, Ezzedine Khachnaoui, provides a comfortable but modest life for his family from farming a small plot of land.

An AFP journalist who visited the family home said it was large, with many rooms, running water and electricity.

According to the relative, Jabeur had been due to graduate from high school later this year and had done well during the first term.

Three of his uncles work in the school: one teaches philosophy, the second is a sports coach and the third is a supervisor.

Jabeur often played the role of imam, leading prayers at the school, but no one ever complained about the sermons he delivered or suggest that he had an "extremist" approach.

But in December, the young man left home without even telling his sister Lubna, with whom he was very close.

His parents later found out that he had gone to conflict-hit Libya, said the relative.

Tunisian authorities have confirmed that Jabeur, and the other gunman Yassine Abidi, went to Libya to train in a militant camp.

At an undisclosed time, Jabeur telephoned his parents using an Iraqi number, but it was not clear if he had actually gone to Iraq.

Tunisia has seen a rise in Islamist extremism since the revolution that ousted veteran strongman Zine El Abidine Ben Ali in 2011.

Authorities say that thousands of young Tunisians have taken up arms alongside jihadist groups battling in Syria and Iraq, while hundreds have returned home from the battlefronts there.