As they approached Ms Ross, it became clear the circumstances appeared suspicious.
"It was immediately obvious things weren't right," she said.
In a statement read to the court, Ms Wilson said blood had pooled around Ms Ross and was coming out of her ears. The beating had been so severe, one of her eyes was swollen completely shut.
The ambulance officer also noticed a 15cm blood spray on the ground next to the victim's head. It could not have been caused by resuscitation attempts, Ms Wilson said.
Bevan Michie, part of the second paramedic crew who attended, said he was immediately struck by the extent of the victim's injuries.
"The thing that stood out to me was the amount of blood and battle signs on the ear," he said in a statement.
"When I cut [Ms Ross's] black jacket, blood was oozing out of it as I cut."
Dunedin Constable Matthew Davidson arrived at the scene shortly afterwards, and told the court he saw a bloody hand print towards the bottom of the driver's door of the woman's work van, metres from her body.
The white vehicle was still running, in gear, with the lights and radio on and was flush against a skip with which it had collided, he said.
The Crown's case is that Merritt had finished his shift earlier that night and snuck back to work specifically to attack Ms Ross.
In the days leading up to the alleged murder, disciplinary proceedings against the defendant had been initiated by Ms Ross and he had recently received a letter outlining her issues with him repeatedly parking in a disabled spot and acting disrespectfully.
Crown prosecutor Richard Smith said a search of the Merritt family's home in Kaikorai two days after Ms Ross's death found a bloodied bundle of clothes and a hammer in an outside wheelie bin.
DNA testing showed the blood was extremely likely to be the victim's, he said.
Defence counsel Anne Stevens said there were gaps in the scientific evidence, which would be raised later in the two-week trial.
The trial continues.
