A private investigator looking into the mysterious disappearance of a nurse and mother of two has revealed new information about her life before she vanished near a Southern California mountain, leaving behind her car and belongings.

Angelica Brophy, 44, was last seen in person dropping off her daughter at a camp in Oceanside on July 6.

Anthony Campbell, the investigator assigned to the case, is now reassessing the dynamics of the missing persons case.

'The reason why everything was left in the car, and the way it was left, it was more a goodbye,' Campbell chillingly told NBC San Diego.

Campbell told NBC San Diego that they learned Brophy had disappeared for a week about 10 years ago and was found gambling in Las Vegas.

'An employee at Harrah's Casino said she was a high-tier gambler and there every other day to get her free chips to gamble that day,' Campbell said.

And Brophy's family's website documenting the timeline of her whereabouts on the day she vanished noted that she visited two casinos that day. 

Surveillance footage then captured her leaving the Harrah's Resort Southern California Casino around 3.30pm.

A parking slip located her at Palomar Mountain State Park about 50 after she left Harrah's. Then she disappeared.

A desperate search ensued, and Brophy remains missing almost three months later.

Campbell believes Brophy is still in Palomar Mountain State Park, where her car was initially found.

In an attempt to not offend the family, Campbell decided to resign as an investigator and instead is working on the case as a volunteer.

A gold necklace or bracelet that closely resembles one of Brophy's necklaces was found on Palomar Mountain State Park trail.

Brophy's brother Ramon Fabregas thinks the jewelry may belong to his sister, although law enforcement cannot confirm it.

Brophy was last pictured with her family out at lunch just 24 hours before she disappeared.

The Daily Mail has reached out to the Oceanside Police Department for comment on Campbell's research.