Elizabeth Nass and Rose Mayr sat on the edge of the Ellicott City bridge dangling their bare feet over a dimly lit Main Street shortly before midnight Monday, a last get-together before parting for their junior year away at college.

"Drinking on top of the Ellicott City sign with @r0se_petals," Nass wrote on Twitter at 11:40 p.m.

At 11:51 p.m, Mayr posted a snapshot of their feet high above the road and what would be a final message: "Levitating."

Moments later, a CSX train traveling along railroad tracks atop the iconic red bridge derailed, burying the 19-year-old best friends in coal. When police recovered their bodies, they were still seated on the edge of the span.

Howard County police, who said those Twitter accounts appeared to belong to the women, are examining the teens' cell phones to verify the messages.

"It's unimaginable," said Mark Mayr, Rose's father. "From 4 a.m. until 8 a.m., it was terrible uncertainty."

The family had to identify her from a photo, said Mark Mayr, who spoke at a candlelight vigil Tuesday night at Mount Hebron High School, where both women graduated in 2010. Rose's mother, Sharon, and her older sister, Anna, also attended the vigil.

Kyle Nass, a cousin of Liz Nass, also spoke briefly, calling her a role model for the many cousins in their large family.

"She was very charismatic, extremely intelligent. She had the biggest heart," he said.

The two had known each other since elementary school and had recently resumed their close friendship, Mark Mayr said.

About 250 people attended the vigil.

"It shows how many friends they had," said Gabby Barnes, a 2012 Hebron graduate who said she danced with Mayr.

A family friend who lives near the accident site said Nass' younger brother called her soon after the crash.

"He said he knew his sister was hanging out here, and he said he knew she was sitting on the bridge," said the teenager, who asked not to be identified out of respect for the family. "He couldn't reach her after he heard about the crash and was really panicked."

She said some of Nass' family went to the site of the accident before daybreak.

In the aftermath of the deaths, a sketch of two vibrant young women emerged.

"They were great students, great people, active in the school," Mount Hebron principal Scott Ruehl said. "It's a tragic loss for not just Mount Hebron and the families but the whole community, because they're such great kids."

Nass attended James Madison University in Virginia, where she was an honor student, majoring in interdisciplinary liberal studies, according to Don Egle, a university spokesman. She was also a member of the Alpha Sigma Alpha sorority, Egle said.

Mayr was studying to be a nurse at the University of Delaware, according to a university spokeswoman.