A San Francisco city employee died after a vehicle being loaded onto a tow truck became unhitched and hit her.

The deadly crash was reported Wednesday in the area of the 500 block of 28th Street.

The city employee has been identified as 34-year-old Lilianna Preciado, who worked for the water district. She was in a ditch with two co-workers when the crash occurred, officials said. Officials said Preciado was a mother of a 2-year-old child.

A witness said the tow truck driver had been complaining about defective equipment on the truck just before the car broke loose.

San Francisco police and other agencies are conducting a full investigation.

“Everything will be measured,” police spokeswoman Officer Grace Gatpandan said. “Cal OSHA is also part of this investigation as well as the Department of Public Health.”

San Francisco Public Utilities Commission General Manager Harlan Kelly released the following statement late Wednesday:

“We are beyond devastated to learn that we lost one of our own employees this afternoon. Lilianna was a dedicated public servant who proudly served as one of only a few female plumbers on our team. Our hearts and prayers are with her family, friends and coworkers tonight as we all mourn this terrible loss.”