A U.S. Border Protection computer showed an Atlanta man with a dangerous form of tuberculosis should have been detained while leaving Canada, but he was allowed free passage into the country.

The U.S. Department of Homeland Security is investigating how Andrew Speaker, 31, slipped in at Champlain, N.Y., despite what the computer showed at the border crossing, as well as a national alert to all ports of entry.

Speaker's passport was scanned into a computer, which showed he was to be held and isolated, and that health officials were to be contacted. None of that happened.

"It was on the screen," said Homeland Security spokesman Russ Knocke. "There's a record of it.

"Not even the finest law enforcement agency is immune to human error," he said.

While Speaker was on his honeymoon in Italy, the Centers for Disease Control and Prevention in Atlanta contacted him and said he needed to go to medical authorities in Rome. Instead, Speaker took a series of short flights before landing in Montreal from Prague on May 24. He then entered the United States by vehicle at Champlain.

The CDC put Speaker on airlines' no-fly list on May 24, not knowing he was already en route to Canada. Two days earlier, the CDC made U.S. Customs and Border Protection aware that Speaker was traveling with a dangerous communicable disease, Knocke said. That's when all U.S. ports of entry were alerted, he said.

The CDC is trying to contact 107 passengers and flight crew members who might have been near Speaker for a prolonged period during his two transatlantic flights. Air France Flight 385 left Atlanta for Paris on May 12.

About 50 of those high-priority passengers have been contacted, CDC spokesman Tom Skinner said. Trying to find passenger phone numbers has slowed the process, he said. Skinner urged concerned travelers to call

1-800-CDC-INFO.

The CDC does not consider Speaker highly contagious, but the consequences would be dire if his disease were to spread.

Speaker entered the United States at a crossing less than an hour from Montreal and was let through in about two minutes, Knocke said.

He said the investigation involves "the possibility of human error." The port officer has been reassigned to another job during the investigation.

Homeland Security also is trying to determine whether Speaker was truthful at the border crossing, Knocke said. "There's a clear record of deceitfulness on the part of the individual," he said, referring to the roundabout way Speaker returned.

Knocke noted that Speaker changed his travel plans, which helped him avoid detection. Instead of returning to Atlanta June 5, he flew back earlier into Canada. Officials in Montreal were unaware that Speaker was to be detained until May 25, the day after he had entered the United States.

Speaker traveled to Europe May 12 for his marriage and honeymoon. At the time, he was diagnosed with multidrug-resistant TB. The CDC contacted him in Rome to tell him his TB was the more serious XDR form.

Knocke said Speaker was stopped at the U.S. border at 6:17 p.m. on May 24 and cleared security at 6:18 p.m.

The CDC contacted Speaker by cellphone between Albany and New York City. He was isolated in New York, then flown to Atlanta, where he was kept in isolation under guard at Grady Memorial Hospital before leaving for Denver on Thursday.

State and local officials said they told Speaker not to travel but didn't have the authority to block his plans.

State health director Dr. Stuart Brown said the incident points out that state and county officials need the power to forcibly quarantine someone. He wants the General Assembly to examine the issue of balancing personal rights and public health.

Fulton County's health director, Dr. Steven Katkowsky, said Speaker was bluntly told May 10 not to travel because he had a potentially deadly disease that he could spread to others.

Speaker told the AJC earlier this week that Fulton officials told him that they "preferred" he not travel. When pressed on what that meant, Speaker said Fulton did not say he could not travel.

Brown asked, what if avian influenza — bird flu — were to become a bigger problem? Local authorities would need the power to restrain the travel of infected people, he said.

"This is a decision that the legal minds need to grapple with," Brown said. "This is based on the common perception in America that individual rights have primacy, and in public health we are weighing that issue at the same time we are trying to protect the public."