The two children killed in a drunken driving-related rollover crash on Sunday evening have been identified by the medical examiner.

The grandmother of Rebecca Morales, 7, and Roman Morales, 10, said the siblings died from injuries they sustained when they were ejected from an SUV driven by Rigaberto Morales, 35, who police said had been drinking prior to the crash.

Investigators said neither of the two children were wearing seat belts and a witness told police that at least one child in the vehicle was standing up before the crash occurred on Southwest Loop 410 and Old Pearsall Road.

Police said a total of six people were in the vehicle at the time -- three adults and three children.

The other four passengers, including Morales and the children's little sister, mother and aunt, were taken to an area hospital.

Investigators on Monday said Morales was driving drunk, speeding and weaving in and out of traffic. He has been charged by proxy with two counts of intoxication manslaughter, two counts of intoxication assault and one count of violation bond/protective order.

He remains in the hospital in serious condition with a head injury.

Meanwhile, on Tuesday night, total strangers joined family and friends of the victims gathered at the accident site for a vigil in their honor.

"If I was to get behind the wheel while intoxicated, I'm not giving a thought to myself or anyone else, and the chance of me surviving will be high, and I just don't want to see it happen to another person," said Marion Smith, who organized the vigil. "I don't want to see another child get hurt."

The children's grandmother said she is hurt by the accident and can't believe her two grandchildren are gone.

She said Morales and his wife were fighting in the vehicle at the time.