LOS ANGELES (CBSLA.com) — A 29-year-old Orange County medical student was detained for two weeks in a Bangkok jail and he isn’t exactly sure why.

The student, Rehan Motiwala, said police in Bangkok never “officially” told him why he was held but he is sure it’s about the secretive no-fly list.

Motiwala, an Anaheim resident, was two weeks late for his Fathers Day reunion with his dad.

At a press conference Friday, Motiwala said, “I’m just really glad to be home today.”

Motiwala, a US citizen, says he was returning from a trip abroad that began last year.

He made several stops — to Pakistan to visit relatives and Indonesia where he joined a conservative Muslim missionary group called Tablighi Jamaat.

But he says when he tried to returned home to the US he was not allowed to board his connecting flight in Bangkok, Thailand.

“I was refused boarding because the State Department said I didn’t have the proper clearance to board,” says Motiwala.

The med student says he was eventually turned over to Thai authorities and put into a filthy detention room for ten days.

“I would have to sleep in very dirty and disgusting beds, with roaches,” says Motiwala.

The Council on American-Islamic Relations ultimately  intervened on Motiwala’s behalf to get him home safely.

KCAL9 Political Reporter Dave Bryan says American and British security officials allege the religious group with which Motiwala worked in Indonesia, may have ties to radical organizations.

It’s possible that’s why he was detained for questioning. But his supporters argue he’s still an American citizen.

“Whatever the government knows or thinks it knows about any individual, is that if they are Americans, they have certain rights, whether they are here on American soil or whether they are stuck in countries abroad,” said Ameena Qazi with the Council On American-Islamic Relations.

For security reasons, the no-fly list is kept secret, reports Bryan.