Identifying people who have been badly injured or killed in a car accident often is challenging, marked by chaos at an accident scene or hospital and by families desperate for information about their loved ones.

Police veterans said authorities have to be careful to avoid misidentifying accident or crime victims.

"Because of all the emotions, we have got to be right," said Bill Louis, assistant police chief in El Mirage.

The families of Abby Guerra and Marlena Cantu hope that reform will be the ultimate outcome of an identity mix-up that drew national attention.

The young women were among five Glendale Ironwood High School graduates returning home from an impromptu weekend trip to Disneyland on July 18 when the SUV they were riding in rolled on a highway outside Phoenix.

About five hours after the accident, state Department of Public Safety officers and officials at St. Joseph's Hospital and Medical Center told Guerra's parents she had died.

Six days later, dental records showed that Guerra, 19, was alive. Her friend, Marlena Cantu, 21, had died.

Such mistakes have happened before. In 2006, a family buried a woman they thought was their daughter, only to learn weeks later that she was still alive. Indiana authorities had mistaken her for a friend who was in the same accident. In the 1990s, friends identified the body of a man who died in a Phoenix motorcycle crash. Then the man walked into the hospital lobby.

Accident chaos

The confusion surrounding a serious accident can complicate officers' attempts to identify the injured or dead, experts said.

Officers may arrive at the scene to find the occupants of the car unconscious and trapped in the wreckage. Purses, CDs and clothes may be strewn in the street. Victims may carry driver's licenses with photographs and addresses that are years old, or have no form of identification at all.

Police and medics focus on taking care of the injured person before asking questions. They sometimes have trouble distinguishing between victims who look alike.

Even family members, dazed in the suddenness of an accident, can be uncertain.

The Cantus wanted to believe authorities who said their daughter was alive. The young woman in the hospital bed was obscured by medical tubes in her mouth. Her face was swollen, much of her hair shaved.

Still, some things didn't seem quite right. Marlena had an extra ear piercing. And her hair was a little darker than her mother, Renee, remembered. Maybe, a nurse said, it was darkened by blood.

Careful identification

Officers have to take steps to get an identification right, even as family members are anxious for answers.

Dennis James, a retired Phoenix police officer who spent 22 years investigating serious accidents, said family members who rush to an accident scene pepper authorities with questions: What happened? Who were they with and why? Is this my child?

Officers may think they know the identity of a victim but have to wait until they can confirm it, James said.

They must strike a balance between appeasing family members and ensuring they share only established facts, said Louis, who has been in law enforcement for more than 30 years.

Police often have questions of their own for the families.

Police will ask about tattoos or birthmarks, said Mike McCullough, who spent eight years investigating accidents with Phoenix police before retiring. They may share a photograph or allow friends or family to see the face of a person who has died in an identification effort.

Police contact officials at the hospital if the victim is being treated there or even go to the emergency room to check for any identifying characteristics.

Hospital staff also often question family members.

Frank Cantu told The Republic that hospital officials asked the families whether their daughters had any identifying characteristics. A nurse went to check on the young woman in the hospital bed after the Guerras said their daughter had a mole on her chest, he said.

The families were soon separated and told that Guerra had died.

The Maricopa County Medical Examiner's Office revealed the mix-up, after the review of dental records.

In Phoenix and elsewhere, authorities consider a medical examiner's review the most solid method of confirming a deceased person's identity.

Possible reform

The Guerra and Cantu families have called for reform. They don't want others to endure mix-ups.

They have asked that families be allowed to view bodies within 24 hours at the Medical Examiner's Office, even if authorities haven't established the identification.

Currently, most families don't see the bodies of loved ones until they are taken, after an autopsy, to a funeral home, a spokeswoman for the Medical Examiner's Office said.

It is unclear whether the Guerra-Cantu mix-up could lead to a change in policy.

Spokeswomen for the Medical Examiner's Office and the hospital have said they will review their procedures to see if updates are needed.

A DPS spokesman said last week that he was unaware of any internal reviews or investigations into the case.