The identities of more than a dozen of the men who hijacked the four planes with knives and box cutters and threats of bombs have been ascertained, says the U.S. government. Attorney General John Ashcroft said 12 to 24 hijackers commandeered the four planes, and a government official said another two dozen or so are believed to have assisted them. About 40 of the men have been accounted for, including those killed in the suicide attacks. Authorities detained at least half a dozen people in Massachusetts and Florida on unrelated local warrants and immigration charges and were questioning them about their possible ties to the hijackers. Officials who spoke on condition of anonymity said they were investigating whether one group of hijackers crossed the Canadian border at a checkpoint and made their way to Boston, where two jet liners were hijacked and flown into the World Trade Center. Two suspects flew from the Portland International Jetport in Maine to Boston, where they boarded the deadly flights, this according to Maine Governor Angus King. The two men apparently were using New Jersey driver’s licenses and left behind a rental car with Massachusetts plates that was impounded and hauled to the Maine State Police crime lab.