Tulsa Apartment Murders Update: Four women all died from a gunshot wound to the head, medical examiner says

(AP) TULSA, Okla. - The Oklahoma Medical Examiner's Office says four women found dead last week at a crime-plagued south Tulsa apartment complex each died from a gunshot wound to the head.

Pictures: Okla. twins killed in apartment shooting

The office noted, however, that full autopsy reports are still pending for 23-year-old twin sisters Rebeika Powell and Kayetie Melchor, 33-year-old Misty Nunley and 55-year-old Julie Jackson.

Investigators have not said how the women all knew each other or why they may have been targeted.

According to court records, police have identified a man who "at a minimum" witnessed the killings at the apartment. That man, who has not been charged or arrested in the quadruple homicide, is being held on unrelated charges in the Tulsa County jail.

A judge increased bond for the man from $11,000 to $250,000.

Complete coverage of the Tulsa apartment murders on Crimesider