1.   The authorities have identified no suspects in the letter bombings.

2.   However, state prosecutors have no witnesses or firm evidence tying the two men to the letter bombings, which have continued since they were detained.

3.   Last year, there were several letter bombings in southern Vietnam.

4.   Two men were found guilty of neo-Nazi activities Thursday and sentenced to prison terms, but acquitted of participating in a series of letter bombings two years ago.

5.   Austria was terrorized by a wave of letter bombings in December that left four people injured.