An employee of a Cambridge organization that provides services to people with developmental disabilities is facing an assault charge.

Waterloo Regional Police say their investigation began around noon Sunday, when they received reports of a 78-year-old man with a developmental disability being assaulted by a woman in a parking lot outside a restaurant on Hespeler Road.

According to police, bystanders tried to stop the assault, but the woman and man ended up driving away in the same van.

Investigators found that the man is a resident of Community Living Cambridge, while the woman works for the same organization.

Police say the man was not seriously injured.

The 61-year-old woman was charged with assault, and police are still investigating.