Tragic: Jamie Minor was missing a month before her body was found trapped in ductwork

The body of a 26-year-old woman who had been missing for more than a month has been found in a restaurant ventilation system.

Jamie Minor, from Austin, Texas, was trying to enter the down town restaurant through its ductwork when she became trapped and died, police said.

It is not clear how many days or even weeks she may have been trapped for before she died and police have yet to determine the exact cause of death - though they do not expect foul play.

They said when her body was found she was 'obviously deceased'.

Jamie - who had a history of mental illness - was last seen on May 23 when she showed up for work as a hostess at the Trace restaurant at the W Austin hotel.

Supervisors were said to have been concerned by what they described as her 'erratic behaviour' and fired her before sending her home.

They arranged for someone to pick her up at 10pm but by the time they arrived she had already left. That is the last time anyone ever heard from her.

She was discovered yesterday in the ductwork leading into Perry's Steakhouse between the first and second floors of the building where she was believed to have been meeting a friend who works there.

Police Commander Julie O'Brien said: 'This appears to be an incredibly tragic accidental death.'

Cmdr O'Brien said police believe Minor left the hotel and walked to the restaurant where she used to work.

Scene: Jamie became stuck in the ductwork of this building in down town Austin where Perry's Steakhouse is located

Dead: The 26-year-old had a history of mental illness and was said to be behaving 'erratically' on the night she became trapped

According to the American Statesman, surveillance camera footage from the building shows that Minor tried to get into Perry's Steakhouse through a side door.

She then tried to enter through a door in the parking garage about 9pm.

Cmdr O'Brien said: 'What we believe for reasons we don't quite understand yet is that Jamie entered the parking garage, went to the third floor and forced entry into the duct system, attempting to get into the restaurant that was located on the ground floor because she had a friend who worked there.'

She explained that the ductwork zigged and zagged inside the building and that Jamie managed to get trapped in an area she wasn't tall enough to get out of and couldn't move forward or back from.

She may have been trapped there days or even weeks before she died and was in a part of the building where her calls for help would never have been heard.

When her parents hadn't heard from her in more than a week they became concerned but it wasn't until June 7 they filed a missing person's report.

Police: Commander Julie O'Brien has called the death a tragic accident

According to the Statesman, on June 2 maintenance workers found personal items belonging to Jamie near an exhaust vent grate on the top floor of a parking garage attached to the Norwood Tower building, where the restaurant is located on the first floor.

On Saturday, homicide detectives, city crews and Austin firefighters broke into the ductwork at the second floor of the garage, and they found an 'obviously deceased person' between the first and second floors, Cmdr O'Brien said.

Jamie's mother Pamela Minor, 59, said: 'I am just heartbroken she made the choices she did. I am very saddened she couldn't get to safety. She probably became frantic. I am very saddened by the suffering she went through.'

She also revealed that her daughter had been struggling with mental illness including bipolar disorder since her early twenties.

A benefit was held for Jamie on Sunday to raise reward money for information her whereabouts, friends and relatives said.

Now, the money may be donated to a non-profit organisation, Mrs Minor said.

In January, following a disagreement with her mother, Jamie left a note on her car, which Pamela Minor keeps framed today.