Confirming the death of a suspected terrorist half a world away can be hard.
Blame it on the fog of war, unreliable local intelligence or overzealous media reports -- either way sometimes a high-profile extremist is declared dead only to reappear suddenly in public or online, alive and well, mocking his enemies.
Here are a few of the most well-known "undead" terrorists, from al Qaeda leader Ayman al-Zawahiri to American-born jihadist rapper Omar Hammami. The latest to join the list: Mokhtar Belmokhtar, suspected mastermind of the Algerian gas plant attack in January 2013.
|Mokhtar Belmokhtar, Suspected In Amenas Attack Mastermind|
More than a month after the Chadian military claimed it had killed suspected terror leader Mokhtar Belmokhtar, a U.S. official told ABC News today that American intelligence is still "not clear" on whether he's actually dead.
Belmokhtar, allegedly the planner behind the deadly January 2013 attack on an Algerian natural gas facility, was supposed to have been killed along with "several" other terrorists when a base he was operating in was "completely destroyed" by the Chadian military in an operation in early March in Africa, according to Chadian military spokesperson Gen. Zacharia Gobongue. A soldier in the Chadian military even took blurry, unclear pictures of a body the military claimed was Belmokhtar's remains.
But after four weeks spent trying to confirm Belmokhtar's death – and in the wake of a local news report in which a spokesperson for Belmokhtar's group purportedly denied Chad's claims – America and its European allies apparently haven't been able to sort it all out.
"Statements earlier this year from officials in the region that Belmokhtar had been killed in the fighting were too definitive," the U.S. official said. "Right now his status is not clear."
Belmokhtar, a former member of al Qaeda in the Islamic Maghreb (AQIM), reportedly created his own terror group after splitting with al Qaeda in recent months. The attack on the gas facility near In Amenas, Algeria claimed dozens of lives, three of them American.
Richard Clarke, a former counter-terrorism advisor for the White House and current ABC News consultant, said that reports of a terrorist's death could cause them to go further underground.
"The 'undead' take special precautions to avoid detection, more so than they normally did before their brush with death," Clarke said. "Eventually, the 'undead' slip up and proof they are alive surfaces."
Belmokhtar was also reported to have been killed in June 2012 and several times before that, according to Reuters.
|Omar Hammami, al Qaeda Rapper|
Omar Hammami, the Alabama-born rapping jihadist also known as Abu Mansoor al-Amriki, has died and come back to life yet again. His latest resurrection was at least the third reboot for the 27-year-old, who has acted as a mouthpiece for al-Shabaab, the Somali branch of Al Qaeda, since arriving in Somalia in 2006.
Hammami was first reported killed while fighting in Somalia in early March 2011. The next month he came back from the dead in style and with a beat, releasing two a cappella English raps -- to little critical acclaim -- in which he begs for martyrdom. As part of al-Amriki's attempt to recruit Western youth for jihad, he has released a half-dozen rap tracks on the internet since 2009.
In July 2011, he was rumored to have been killed by a Predator drone, but later resurfaced.
In March 2012, Hammami released a video in which he said he feared for his life at the hands of his al-Shabaab comrades.
"To whomever it may reach from the Muslims, from Abu [Mansoor] al-Amriki, I record this message today because I feel that my life may be endangered by [al-Shabaab] due to some differences that occurred between us regarding matters of the Shariah [Islamic law] and matters of the strategy," Hammami says in the video.
Via its official Twitter account, Shabaab expressed surprise at Hammami's fears, denied he was endangered and said he still enjoyed all the "privileges of brotherhood.
Within weeks, however, rumors surfaced that Amriki had been executed by al Shabaab, a casualty of recent doctrinal infighting. Somali media reported, and Western media repeated, a scenario in which Amriki was beheaded on the orders of a powerful rival on April 4.
Two weeks later, local Somalia media reported that Amriki had been sighted alive and well.
ABC News' Matthew Cole and Jason Ryan contributed to this report.
|Ayman al-Zawahiri, New al Qaeda Leader|
Formerly Osama bin Laden's deputy, Ayman al-Zawahiri rose to the top of al Qaeda after bin Laden was killed by U.S. Navy SEALs in May.
But according to reports from Pakistani military officials in 2006, al-Zawahiri should not be around to take up the terror mantle. Al-Zawahiri was rumored to have been killed in a U.S. airstrike in January that year in Pakistan along with several high-level al Qaeda commanders. Al-Zawahiri was not at the target location and later released a video taunting then-President Bush, saying, "Bush, do you know where I am?"
In 2008 rumors of Zawahiri's death began circulating again after CBS News reported he was severely injured in another air strike. That report was disputed and al-Zawahiri again resurfaced in online videos after the incident.
Al-Zawahiri, as al Qaeda's new commander, is right at the top of America's most wanted list and the U.S. government is offering $25 million for any information leading to his capture.
|Doku Umarov, Chechen Militant|
Chechen militant Doku Umarov came to international prominance in February after he claimed responsibility for plotting the Moscow airport bombing that claimed 36 lives the month before.
Russian authorities have been going after Umarov for years -- so long that he's been rumored to have been killed more than a handful of times. In just the months after the bombing, Russian news reported multiple military operations in which Umarov was thought to have been taken out.
Most recently, Russian authorities suggested Umarov was killed in an air strike in April and reportedly carried out DNA testing on the bodies in hopes of matching them to Umarov. But on the same day Russia's state news agency reported scientists were testing the DNA, a man claiming to be Umarov called into Radio Free Europe to announce he was "alive and well."
He is still Russia's most wanted man in the Caucasus, according to Russia's RIA Novosti.
|Adam Gadahn, California al Qaeda|
Adam Gadahn, born Adam Pearlman, left his home in California for Pakistan more than a decade ago and joined al Qaeda. He has appeared in several al Qaeda videos, the latest of which features him telling Muslims to take up arms and shoot Americans.
In 2008, a Pakistani newspaper reported Gadahn may have been killed in an airstrike inside Pakistan. But a U.S. official told ABC News that at the time Gadahn was "not that important" and was not the target of the strike.
Later the same year, several news organizations reported Gadahn had been killed in a Predator drone strike. Both the rumors proved false months later when Gadahn appeared in a video online discussing current events.
Gadahn is wanted for "treason and material support to al Qaeda" and the U.S. Department of Justice is offering $1 million for information leading to his capture.
|Mullah Omar, Taliban Leader|
It was the middle of the night in Afghanistan in July 2011 when local journalists received a text message from a Taliban spokesperson with stunning news: Mullah Omar, the one-eyed leader of the Taliban and former comrade in arms of Osama bin Laden, was dead.
The Taliban's official website appeared to confirm the news and posted its own announcement on the passing of one of the world's most wanted men.
But Mullah Omar isn't dead -- at least not as far as U.S. officials know. Another Taliban spokesman quickly contacted members of the media to say Omar is alive and doing fine, thank you. He claimed that both the Taliban's website and phone network had been hacked by a "cunning enemy" who spread the false report.
|Mohammad Ilyas Kashmiri, On Terror Short List|
Mohammad Ilyas Kashmiri may not be as well known as other terror leaders, but as the head of the Kashmiri group Harakat-ul Jihad-i-Islami, Kashmiri had the distinction of being on a list of five suspected terrorists the U.S. asked Pakistan to help neutralize.
Kashmiri, whose group is believed to be responsible for several violent attacks in Pakistan and India, was rumored to have been killed twice in drone strikes -- once in September 2009 and then again in Pakistan in June in 2011.
Since the latest strike, conflicting reports have emerged about Kashmiri's fate. One Pakistani news outlet reported that he had survived the June 2011 attack and was still operating in Pakistan, while Western news outlets reported U.S. officials were "99 percent" sure Kashmiri had been killed. In March 2012, an al Qaeda spokesman issuing a statement on Koran desecration by U.S. troops in Afghanistan also seemed to confirm Kashmiri's death.