The Metropolitan Police Department Wednesday held a memorial service for its police dogs.

The event, held at a cemetery for animals in Tokyo's Itabashi Ward, was attended by 40 people who worked with the dogs.

"The police dogs are our colleagues. I put my hands together and thanked them," said Hiroshi Takada, director at the MPD crime lab.

The Metropolitan Police Department has held services for its police dogs every fall and spring since 1968. Currently, 229 dogs rest in the cemetery.

The police said two dogs had passed away since the last memorial service.

A dog named Kuroota that died in March was mobilized 407 times since 2004 and made contributions such as finding a camera stolen by a thief who threw it away while on the run in Tokyo's Katsushika Ward.