An international investigation is underway to identify the masked executioner of American journalist James Foley. The ISIS terrorist who carried out the beheading in a YouTube video spoke with a distinct British accent, leading to suspicion that he may be one of many British citizens who have traveled to Syria and Iraq to join ISIS or other extremist groups.

Amy Kellogg reported the latest this morning, pointing to a Guardian newspaper report that quoted a former hostage who had been held in Syria.

The person told the paper that he recognized the voice of the masked man, saying he is educated and goes by the nickname "John."

The former hostage said that he and others being held in Syria actually started calling their British-sounding captors "The Beatles."

Guardian reporter Martin Chulov says the man who killed Foley is believed to be the leader a group of British fighters holding foreign hostages in Raqqa, Syria.

Some of the hostages are believed to have been released after ransoms were paid. The U.S. government does not negotiate ransom payments with terror groups.