Investigators in the U.S. and overseas are carefully retracing the movements of a man arrested Tuesday at a Florida airport with bomb-making materials in his luggage to determine whom he associated with as a contractor in Iraq, ABC News has learned.
It remained unclear Thursday whether Brown's apparent mental problems prompted him to tell authorities after his arrest that he was planning on building a pipe bomb to show his friends in his native Jamaica or whether he harbored more nefarious motives.
Key questions in what federal sources describe to ABC News as a very active investigation include whether Brown had any contact with extremists in Iraq, and who may have given him instructions on how to build a pipe bomb. One senior official cautioned that the investigation was still in it's initial stages and that it remained unclear whether Brown was simply suffering mental problems or whether he posed a real danger.
While the bomb-making materials were discovered in checked luggage, investigators said they want to be sure that Brown - who was en route to Jamaica - wasn't planning to fly to the island, assemble the bomb, and then detonate it on a return trip to the U.S, sources told ABC News.
The quickening pace of the investigation seems to indicate the seriousness with which the federal government is taking threats to airline security - even those that appear on their face to be the products of mental illness.
Brown, 32, was reportedly working for a military contractor that provides logistical and technical support to the American military overseas. Exactly how much time he spent there remains unclear.
Federal behavioral specialists spotted Kevin Brown acting suspiciously around noon on Tuesday in the ticketing area of Orlando National Airport.
A search of his luggage revealed two pipes with end cap holes in them, two glass bottles apparently containing the explosive nitro-methane, two prescription bottles full of BB pellets, a model rocket igniter, batteries, lighter fluid and instructions on how to build the bomb, according to an FBI statement.
Brown was also in possession of a laptop, which is also being analyzed. The laptop was found inside a carry-on backpack, apart from the bomb-making materials.
The arrest cause some tense moments at Orlando national airport on Tuesday.Watch video of the man's arrest.
Brown told authorities he was bought the materials in Gainsville, Florida and was planning on detonating the pipe bomb on a tree stump in his native island nation. At another point, he told investigators he was going to show his friends how to build a bomb like the ones he said he saw in Iraq, according a criminal complaint.
Fellow travelers said they thought there was something wrong with Brown.
"He was acting all weird, shaking left to right, up and down,'' passenger Jason Doyle told ABC News affiliate >WFTV. "He looked like a crazy man, basically."
When officers x-rayed Brown's luggage they found the bomb-making materials and took him into custody.
"TSA workers told us to move away from the windows, that the man over there was a very bad man," said another Air Jamaica passenger, Yvonne Turner.
The security scare caused long delayed flights and caused long lines at the international airport, WFTV reported.
Clarence Counts, Brown's court-appointed public defender, declined to comment as he prepared for a formal bond hearing Thursday, according to the Associated Press.
A Jamaican newspaper quoted Brown's mother in law in Thursday as saying Brown "hasn't been the same" since he returned from Iraq.
"He sees things, he hears things and he just doesn't act normal,'' Karen Holt told the newspaper. "In fact, he is extremely distant."
Holt also said Brown had been distraught since his mother, a hotelier, was strangled at a resort she worked at on the island.