DETROIT -

After more than a dozen deaths and nearly 50 accidents, General Motors is set to announce Thursday morning how a design flaw remained concealed for years.

Related: GM sorry for sending recall notices to victims' families

The feds have already fined the company $35 million for failing to disclose the problem in a timely manner. GM CEO Mary Barra will address employees and then the media Wednesday.

Why did it take more than a decade for GM to acknowledge an ignition switch defect which has been linked to at least 13 deaths?

The findings of the internal investigation into what happened and why is set to be announced Thursday but the expectation is the blame won't be placed on a single person but entire departments.

But expect GM's engineering department to take it on the chin, along with the company's internal review procedures.

Barra's already made changes. Expect the report to be the beginning of more to come.

Complete coverage: GM ignition switch recall investigation