Possible breakthrough in ID of ISIS terrorist in James Foley death video

LOS ANGELES (KABC) -- When an ISIS terrorist put his knife to American James Foley's throat earlier this week, he likely believed his identity was safely hidden. But there appears to be a breakthrough in the case.

ABC News has learned that U.S. and British forces are closing in on the identity of the so-called Jihadi John.

"We are confident he will be identified," a senior U.S. official told ABC News, and they believe he will be identified soon.

Using voice recognition technology, they are working to match the voice on the Foley video with a database of British nationals suspected of terrorist ties. They are also attempting to match the voice with communications now being monitored from the Middle East.

Meantime in England, British intelligence officials are zeroing in on several London residents who joined ISIS, an Islamic army now spreading terror and death in Syria and Iraq. The terrorists are threatening to execute a second American journalist, Steven Sotloff.

ABC News has learned that two more Americans are being held by the Islamist militant army, which has warned it will kill all hostages if the U.S. doesn't stop a barrage of nearly 100 air strikes against their positions in Iraq, and that its fighters will bring terror to the U.S., prompting a Homeland Security warning.

"The really chilling thing about the warning that they have issued to local law enforcement is that ISIS is believed to be able to attack U.S. interest with little warning at all," said Jonathan Karl with ABC News.

In Iraq, it was another deadly day. Car bombs and suicide bombers in three cities left at least 24 dead, and police say more than 50 more were wounded.

This as the White House weighs its military options against ISIS. Bombing runs continued around the Mosul Dam. The Defense Department says the U.S. military has carried out 61 airstrikes near the dam in the last two weeks. Those airstrikes could be expanded into Syria, where the U.S. has largely stayed out.

The military options include hitting ISIS with airstrikes in Syria, where the U.S. has largely stayed out of a more than three-year long war that has claimed nearly 200,000 lives.

President Barack Obama, still on vacation, will face some tough decisions when he heads back to Washington. He is set to return to the White House on Sunday night.