Police say the images could upset the victims of crime
A Japanese company has launched an online slot machine game featuring mug-shots of wanted fugitives.
Slot Detective works like a traditional slot machine but with human faces instead of lemons and cherries.
Software manufacturer Famista Inc says it hopes the free game will help catch Japan's most-wanted suspects.
However, police say the use of the photos is inappropriate, although they have stopped short of calling for the game to be banned.
Famista spokesman Takashi Saito said the game drew on the popularity in Japan of "pachinko", a Japanese version of pinball played in thousands of noisy parlours across the country for prizes that can be exchanged for cash.
Mr Saito said Famista thought Slot Detective - accessed by computer or mobile phone - could be a way to contribute to society.
"There are many internet sites that display photos of those on the wanted list, but they are not necessarily visited frequently," he said.
"By mixing it with entertainment, we thought we can make some contribution to the police efforts."
He said that about 100,000 people had visited the site within hours of its launch on Friday, briefly stalling a server.
As with a traditional slot machine, when three of the same picture line up, the player wins.
However, the jackpots bring details of the suspect and the crime, as well as how to give tips to police and the amount of any reward offered.
The National Police Agency said that although they appreciated the sentiment, the game "inappropriately uses police property for entertainment and could distress victims".
"The mug shots of the suspects should be used in a more socially acceptable manner," the agency said in a statement.
Mr Saito said the only criticism from users so far was that some had been "scared by the fierce look of the murder suspects".