Send an email.

The National Anti-Corruption Commission's complaint centre page lists three ways to report corruption or misconduct: a letter to the NACC Secretary-General, an online complaint system, and email to complaint.nacc@nacc.go.th. If you have first-hand information or documents about the ownership of Burijaroen Construction Limited Partnership, or about Transport Ministry contracts it received, you can submit them through the online system or by email, quoting the Saksayam Chidchob asset-concealment case. State what you know, how you know it, and attach any documents; do not send speculation.