The promise of 70 or 72 virgins upon martyrdom has become a familiar expression in discussions among Islamic extremists, but a recent terror indictment raises the peculiar question of whether the incentive has been increased.

The case involves a man suspected of conspiring with a terrorist network responsible for the deaths of five U.S. soldiers in Iraq. He was arrested Wednesday in Canada, according to a statement from the U.S. attorney's office for the Eastern District of New York.

Faruq Khalil Muhammad, 38, was charged with conspiring to kill Americans abroad and providing material support to a terrorist network that conducted suicide bombings in Iraq, the statement said.

The complaint quotes from wiretaps of conversations between the defendant and the potential suicide bombers he is alleged to having aided.

In one snippet of conversation from March 2009, the defendant is encouraging a reluctant "Fighter 5" who is concerned about his mother. In the course of encouraging "Fighter 5," the complaint shows an inflation in the promise of virgins after martyrdom.

"May God give you 74 to marry. We want virgins of paradise, not the ones here," said "Fighter 5," according to the criminal complaint.

"You come short, brother," the complaint quotes Muhammad as responding. "God is more generous than that. It's supposed to be 76."

The promise of 76 is higher than even the defendant believes is traditionally due. In October 2009, according to the complaint, the defendant explains to his own mother the rewards of jihad.

"Do you know mother that when a martyr dies, he would have 7 characteristics. First, he receives forgiveness for all his sins, then he gets to see his own seat in paradise," the complaint alleges Muhamad said. "Also he gets to have 70 virgins."

So is the promised reward of martyrdom suffering from some sort of spiritual inflation? Is 70 no longer enough incentive?

"It seems to be an inaccurate and carelessly cited figure," said Dr. John Esposito, a professor at Georgetown University and author of The Future of Islam.

There is nothing in the Quran that rewards a suicide bomber, or martyr, with virgins, Esposito said.

"This has become a popular belief in some circles but is not based on scripture," Esposito explained.

The Quran does speak of "houris," dark-eyed or black-eyed virgins, noted Esposito, as a reward for men in paradise, but not specifically for martyrdom.

The number, typically 70 or 72, is not in the Quran, said Esposito, but rather comes from the oral tradition.

The focus on virgins as a reward for martyrdom is a modern phenomena said Salah Hassan, an associate professor at Michigan State University and coordinator of the school's Islam, Muslim and Journalism Education project. Interestingly, Hassan said, the virgin promise is one that is used both by jihadists to entice recruits and on the other side by those critical of Islam.

"It is polarized views sharing a particular image for different ends," Hassan said.

"They are in a way tapping into a public discourse in the U.S. because it is not widely cited by Muslims to promote jihad. It is more recent usage," Hassan said. "My sense is that is very often cited in the U.S. as a way of basically showing how vulgar Muslim piety is. To a degree that these images mean anything, they are interpretable. It is a metaphor. There is obviously not 72 virgins waiting for anybody in paradise."

Hassan said that inflated rhetoric is a hallmark of jihadist discourse, noting that the defendant is alleged to have written in an e-mail message "he is not just 100% but 1,000,000% with you. He is with you on the doctrine, the loyalty and the enmity and everything one million percent."

"These guys are obviously inflating and I am sure the rhetoric is inflated," Hassan observed. The promise of 76 is part of that exaggeration.

"The act itself is exaggerated. The idea you would blow yourself up is excessive. So it is all in excess. How would you justify an excessive thing?" said Hassan. "Muslims think (of) suicide bombing as unacceptable. It is not Muslim. It is weird extremism that looks for justification within extremism for rationales and recruits."

Brian Fishman, a terrorist analyst at the New America Foundation and researcher for the Combating Terrorism Center at West Point, said, "They are rhetorically upping the ante to convince a guy who is wavering."

Fishman said the promise of virgins in exchange for martyrdom continues to be a common recruiting element in the online jihadist forums he monitors. Fishman said a much less talked-about incentive is the promise that a martyr can name 70 family members to heaven. But Fishman said the real recruiting pitch is to defend an Islamic country from an infidel force.

"Once you do that, you did a wonderful deed, you get the rewards," said Fishman.

Raising the number of post-martyrdom virgins to 76 does not reflect "a real ideological shift," concluded Fishman.

In the end, "Fighter 5" was stopped before he could complete his mission, turned back by the Tunisian government trying to cross into Libya, according to the complaint.