Laura VanRyn, right, was killed in a car crash on April 26. Her parents have been keeping vigil over her friend Whitney Cerak as she slowly emerged from a coma after they were told that she was their daughter and that Cerak had been killed. ((Taylor University/Associated Press))

In a heartbreaking mix-up, a family kept a bedside vigil for a young woman they believed was their daughter as she spent weeks in a coma following a horrific car crash. They said on Wednesday that their daughter had in fact been killed in the wreck.

Laura VanRyn, 22, died on April 26. Her parents have been watching over her friend Whitney Cerak since then as she slowly emerged from a coma.

The two young women, both students at Indiana's Taylor University, were remarkably similar in build and appearance. Cerak's injuries left her face swollen, with broken bones, cuts and bruises.

Cerak's parents, preferring to remember her before the crash, chose not to look at the body.

The VanRyn family has been keeping a blog offering updates on their vigil at a rehabilitation centre in Grand Rapids, Mich.

"Our hearts are aching as we have learned that the young woman we have been taking care of over the past five weeks has not been our dear Laura, but instead a fellow Taylor student of hers, Whitney Cerak," the VanRyns said in Wednesday's entry.

Their suspicions were raised earlier, however. They reported on the blog that some things didn't seem right as the young woman began to emerge from the coma.

VanRyn's boyfriend first raised questions, and her father became suspicious when she referred to him by a pet name he didn't recognize.

The coroner's office apologized for the mistake.

Coroner Ron Mowery said acquaintances of the students had identified the survivor as VanRyn, and no scientific tests were immediately conducted to verify the identification.

Dental records were used this week to confirm the surviving woman was Cerak.

VanRyn was among four students and a university employee killed when a tractor-trailer drifted across a highway median and slammed into their van. The people in the van worked for the school's dining services and had been setting up a banquet for the inauguration of a new school president.

Mowery said the accident scene had been strewn with purses and wallets.

Most of the crash victims had funerals with closed caskets.

A memorial service for VanRyn is scheduled Sunday in Grand Rapids.