A court in Bahrain sentenced a cyber activist to six months in jail on Thursday after convicting him of defaming the Gulf kingdom's monarch in comments posted online, lawyers said.
The man, whose name was not given, is part of a group of four facing the same charge over comments posted on Twitter and who were arrested last month.
The remainder of the group will be sentenced by the same criminal court on Monday, the lawyers said.
The defendants denied the charges when they first appeared in court on October 22.
On October 17, the government announced the arrests, promising a swift and "urgent trial before a criminal court."
The prosecution later said it had "interrogated the accused and ordered them to be held in custody for seven days pending trial."
Regular demonstrations have shaken Bahrain since it crushed a Shiite-led uprising against the ruling Sunni regime in March last year.
The kingdom came under strong criticism from international rights groups over the deadly crackdown.
According to the International Federation for Human Rights, a total of 80 people have been killed in Bahrain since the violence began on February 14, 2011.