Stamford police are investigating the death of a woman this morning after the car she was riding in slammed into a utility pole. Investigators say the accident happened at around 7:30 a.m. on Halloween Boulevard near Jefferson Street. They say 86-year-old Carmela Avazia was driving the vehicle while her sister, 81-year-old Antoinette Palmierri, sat in the passenger's seat. Police say the crash may have been caused by a mechanical issue, and witnesses say the car was accelerating shortly before impact. Neither of the victims was wearing a seat belt. Both women were rushed to Stamford Hospital, where Palmierri was pronounced dead. Avazia is currently listed in fair condition. Police are planning a full inspection of the car to determine the cause.