Tamils are known to carry cyanide; if the mission fails and they are captured, they're supposed to kill themselves, as dead men tell no tales.
No way does this have anything to do with Sri Lanka issues or rebels, other than incidental. Think about it, why would a LTTE suicide bomber take down an AA flight from Paris-Miami? Suspicion would focus on Arab terrorism, and no publicity for Sri Lanka issues. Unless we hear of it in the next day or so, he left no explanation note, his passenger list name is English, all evidence at the bottom of the ocean. Who associates American Airlines, Paris-Miami, or even the US with Sri Lanka issues? So why bother?
He's got a Muslim connection, no doubt about it.