Three months later, five defendants who stood trial were convicted.
All four defendants were convicted last week on every count brought against them.
If the defendants are convicted, they could face the death penalty.
The three defendants were charged and convicted after the law was passed in 1994.
A defendant can only be convicted of the specific crime with which they were charged.
The trial judge refused to allow the evidence and the defendant was convicted.
One defendant was eventually convicted and sentenced to death three times.
The defendant was convicted and is serving a life term in prison.
The 12 defendants were convicted in Leon, about 55 miles west of the capital, news reports said.
But nearly all those interviewed believed that the defendants would be convicted.