A life-size hologram of a police officer now stands in a Seoul park.
The projection has cut reported crimes during its active hours by about 22 per cent, official data show.
The figure covers incidents reported while the hologram operates at the site.
The 3D image measures roughly 1.7 metres (5ft 6in) and wears full uniform.
The Seoul Metropolitan Police Agency modelled the projection on a real officer, the E-daily newspaper reported.
An officer at the local station told The Chosun Daily that they chose the dress uniform so the hologram could be displayed in all seasons.
“It was suitable for the entire year,” the official said.
The police also said the hologram appeals to the area’s sizable foreign population.
The digital officer appears nightly at Jodong No 3 Park in central Seoul.
It shows up between 7pm and 10pm, glowing blue in the dark.
Every two minutes the projection delivers a pre-recorded message, then vanishes.
“You are being watched by security cameras and in the event of violence or other emergencies, the police will respond in real time,” the message warns.
South Korean tech firm Hologrammica developed the system.
The device has operated since last October under the city’s “Safe Park” programme.
The programme targets locations prone to public disorder, such as drunkenness and violent behaviour, that require increased policing.
Although the hologram cannot make arrests, officials say its presence influences behaviour.
The police attribute the drop in crime to the hologram’s psychological deterrent.