Witnesses said the suspect stepped out of his car, pulled out a hand gun and opened fire on a crowd of over 1,000 protesters.
Villagers complained that the new location lacks enough clean water, electricity, roads, schools and access to health care.
At least 50 people, whose houses were bulldozed early January, said their names are not in the new housing list.
Lt. Gen. Chhoeun Chanthan was found guilty for breach of confidence, distribution and selling of weapons and mismanagement.
Judge Pol Sam Oeun who heard the case in the appeal court said the verdict will be announced on 14 March.
Cambodia is scheduled to hold local commune council elections nationwide in June this year.
On Monday, three female workers were attacked by an unknown gunman while protesting for a pay raise and better working conditions.
The women suffered wounds from handgun shots to their arms, chest, or back.
The renovation will lead to thousands of families to be moved from their homes along the railway in the process.
Police seized weapons and ammunition in an Aug. 13 raid last year in Phnom Penh’s Chamkarmon district.
Nai Nep and Thim Thos, a 49-year-old commune official for the party, were questioned for two hours on Tuesday.
Professor John Greenman began offering such trips in 2010.