Twice in the last year, U.S. forces have come within minutes of catching one of the leading faces of terror, Jordanian militant Abu Musab al-Zarqawi, American and Jordanian officials told ABC News.
Each time Zarqawi has escaped capture, and some officials suspect he is being tipped off.
"There's absolutely no question that Zarqawi has the kind of logistical knowledge and logistical support to evade all kinds of surveillance," said former French defense official Alexis Debat, now an ABC News consultant.
A senior U.S. official told ABC News tonight that catching Zarqawi, and soon, is of the highest priority, with every available technique and technology being deployed for the search.
Many of the recent U.S. airstrikes have targeted Zarqawi, including a missile attack last Friday, which killed one of his top deputies, Sheik Abu Anas al-Shami.
But officials say the 37-year-old Zarqawi has remained as elusive as ever, despite a $25 million bounty on his head.
"It's extremely hard to find one man where much of the population supports insurgency and where somebody is surrounded by bodyguards and a strong network to protect him," said ABC News consultant and military analyst Tony Cordesman.
Officials say Zarqawi has established a kind of military command structure for his group, the Al Tawhid Wal Jihad, and is based in Fallujah, a town about 40 miles west of Baghdad. One recent intelligence estimate puts the number of his followers in Iraq at about 1,000 men, mostly non-Iraqis and including explosives and weapons experts.
"And he almost certainly has intelligence sources inside the Iraqi government and inside the U.S., probably Iraqi advisers or translators," Cordesman warned. "So he can often find our picture of vulnerability, the moment at which to strike."
According to one report, Zarqawi now has commanders and men across Iraq. Most are thought to be in Fallujah and Mosul, with smaller squadrons in Baghdad and other cities, including one close to the Syrian border.
"He seems to have a logistic group, a finance group," Cordesman said. "We don't know the exact structure but from his activities there is a high level of discipline."
Most of Zarqawi's inner circle comes from his hometown in Jordan, the city of Zarqa, from which he took the name Zarqawi. Born Ahmed Fadeel Al Khalayleh, residents and local police told ABC News that he was a teenage street thug and drug user who once ran a video store. Zarqawi's wife and four children still live in Zarqa, including a 7-year-old son, Musab.
Still, no one has acknowledged seeing Zarqawi since he was released from prison in a general amnesty five years ago. In that time, he has become one of the most feared and sought-after men in the world, a master of disguise known for his ease in switching from Arab to Western dress.
U.S. officials say he has distinctive tattoos on his hands, and analysts have used them in attempts to identify Zarqawi in the recent videos showing the beheadings of American hostages Eugene Armstrong and Jack Hensley. Zarqawi and the Al Tawhid Wal Jihad have taken responsibility for the executions.
And while the brutalities carried out by Zarqawi and his group have received the most press attention, U.S. officials say they are actually more worried about Zarqawi's continued fascination with chemicals.