A catastrophic North Carolina car crash has killed a Mechanic Falls woman and maimed her husband, a local soldier who had recently returned from Iraq.

Gretchen Dunn, 36, died instantly in the Wednesday morning crash when the couple’s 2006 Mazda 350Z careened off a curve on a stretch of two-lane blacktop near Lillington, N.C. Dunn was not wearing her seat belt. The car was driven by James and speeding at about 100 miles per hour, so fast that the convertible broke in half on impact, police said Friday.

“They just lost it in the curve,” Master Trooper D.M. Cole of the North Carolina Highway Patrol said.

Gretchen’s husband, Army Chief Warrant Officer James Dunn, 36, was badly hurt in the crash, taken from the scene by helicopter to the University of North Carolina Hospitals at Chapel Hill.

The Mechanic Falls native was listed Friday in “critical but stable” condition.

The accident left the soldier with crushed legs. His left leg was later amputated below the knee.

Chief Warrant Officer Dunn had been home for less than a day, arriving at Fort Bragg, N.C., late Tuesday after a three-month deployment to Iraq.

The accident has left the family “utterly devastated,” said Gretchen’s sister, Cindy O’Connor, speaking from her parents home in Mechanic Falls.

She described Gretchen as her “best friend in the world.”

“She is beautiful, bright, funny and very devoted to her family,” O’Connor said. “She had everything going for her. And she was a hard worker.”

The couple have a 13-year-old son, Matthew.

“We’re just praying for Matt and James,” O’Connor said.

In the wake of the crash, James has been treated for a broken shoulder and broken ribs. He has yet to regain consciousness, she said.

Immediately after the crash, James’ mother and father, Phil and Mona Dunn of Mechanic Falls, and his sister, Alicia Dunn, flew to North Carolina to be at James’ bedside and care for Matthew.

They were joined by a contingent of Army friends and colleagues.

“They’re taking care of them the best they can,” said Lt. Col. Time Nye, a spokesman for the Army’s Special Operations Command, headquartered at Fort Bragg.

James had been working as an intelligence analyst for the command.

“They’ve been fabulous, calling us several times a day,” O’Connor said of the Army, which has posted a soldier to be with her sister’s body.

Gretchen and James were childhood sweethearts. They met when they were 13 and married one year after they graduated from Edward Little High School, O’Connor said.

“Through the Army, they’ve been all over the world,” she said.

Yet the sisters had remained close.

An hour before the crash, the two had talked on the phone. Gretchen was excited that James had returned, O’Connor said. The reunited couple was getting ready to go out and the call was cut short.

The family questions what happened in the crash. Gretchen was “religious” about wearing her seat belt, O’Connor said.

“She’s not here to tell us what happened,” O’Connor said.

Gretchen’s mother and father, Charlie and Sandy Millett, are remaining in Maine for the return of their daughter’s body.

“It’s not supposed to happen like this,” O’Connor said.