Eugene, OR -

Almost a year after the child died, a medical examiner has ruled the death of a 4-month-old Eugene boy a homicide. Authorities say the youth suffered significant brain trauma consistent with having been violently shaken.

The Eugene Register-Guard reports police were called to the child's home in southwest Eugene on Nov. 13, 2012.

But police didn't reveal the death until May, after the newspaper asked about an unexplained homicide in an annual report.

A detective said disclosing information would have impeded the investigation.

Police say the child's mother and boyfriend have been questioned. No names have been made public.

Authorities say they are waiting for a written report from the medical examiner