Four men who dressed like high school students on Wednesday admitted committing multiple burglaries in public housing estates last year in a working class district in the northwestern New Territories of Hong Kong.

The quartet, aged between 22 and 33, meticulously planned their robberies by pretending to be students when they targeted more than 1,800 homes in Tin Shui Wai early last year, Sing Tao Daily reported.

Each defendant had earlier pleaded guilty to burglary in the District Court and each were jailed for 16 months on Wednesday. During sentencing, the judge said their crimes were well-organized, with professional planning and support.

When police officers arrested the quartet they were wearing sweaters, dark pants and black leather shoes, just like high school students. Police also found a few master keys, gloves, masks and wigs in the getaway car the group used, Apple Daily reported.

The prosecutor said that a mobile phone the police had seized contained 52 photos listing details on 1,863 flats. Of those flats, more than 100 had been burgled and over 500 entries had phrases next to them such as “can break in” and “people in the flat.”