The cartoonist who drew the cover of the first issue of the French satirical weekly Charlie Hebdo after eight of its staff members were killed by Islamist terrorists in January has announced he is leaving the magazine.

Renald Luzier, who draws under the pen name Luz, told the French newspaper Liberation that each issue is "torture, because the others are no longer there." His resignation will take effect in September.

"Spending sleepless nights summoning the dead, wondering what Charb, Cabu, Honore, Tignous would have done is exhausting," Luzier said, referring to colleagues who were killed by two brothers linked to the Al Qaeda in the Arabian Peninsula terror group.

Luzier's cover of the magazine's Jan. 13 issue, the first after the Jan 7 massacre that killed 12 people in all, featured the Muslim prophet Muhammad holding a sign carrying the popular slogan "Je suis Charlie" [I am Charlie] beneath the headline "Tout est pardonne", or "All is forgiven". The issue was sold worldwide as part of a massive outpouring of support for Charlie Hebdo after the attack, which was carried out in retaliation for the paper's prior depictions of Muhammad.

Luzier has worked at Charlie Hebdo since 1992. He denied that his departure had anything to do with widely reported tensions at the magazine. 

Charlie Hebdo, which continually operated on the verge of bankruptcy prior to this year, received the benefit of a manifold increase in sales and millions of euros in donations after the massacre. French media report that the sudden windfall has led to a rift between the editorial staff and management over dispersal of the money. The magazine's editor and publisher said a special commission will determine how to use the funds.

The Associated Press contributed to this report.

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