"To commence an investigation" means to begin or start an investigation. It refers to the initial stage where the process of gathering information, facts, and evidence starts to understand a specific situation or incident. Full definition
Police in the area have already commenced investigations into the accident, which the company said it is cooperating with. (3news.com)
He argued that the fact that the body mandated to handle such cases has already commenced investigations, it was unnecessary for the minority to call for independent parliamentary investigations into the issue. (ghanapoliticsonline.com)
Soon after the launch, the firm said it would commence an investigation into whether any employees may have violated those rules. (coindesk.com)