The Criminal Court on Friday handed down an 18-year prison sentence for the mastermind of the gang that robbed the home of former permanent secretary for transport Supoj Saplom in November 2011 - a crime that sparked allegations of "unusual wealth".
Singthong Chaichomchuen's prison term was then reduced to 12 years by the court because his testimony was deemed useful.
Two other members of his gang were also sentenced to 18 years, their terms reduced to nine years because they confessed to committing the robbery.
The fourth, fifth, sixth and ninth defendants named in the case were each sentenced to five years in jail for receiving stolen property.
In the case of the fourth and sixth defendants the terms were cut to two years and six months on their confessions. The fifth and ninth defendants' jail terms were each reduced to three years and four months because they gave useful testimony.
The eighth defendant was sentenced to eight years in prison for supporting the robbery, while the seventh defendant was acquitted.
The court also ordered the return to Mr Supoj of 18 million baht cash seized from the gang.
The money was stolen from Mr Supoj's home while he was at his daughter's wedding ceremony. The thieves claimed there was more cash stashed in bags in the house than they could carry away.