The 26-year-old baby sitter from Fujimi, Saitama Prefecture, under arrest for allegedly abandoning the body of a 2-year-old boy who had been in his care, had offered his services under a fictitious name, police said Wednesday.

Yuji Motte was arrested Tuesday after police discovered the body of Riku Yamada in his apartment the day before.

The boy's 8-month-old younger brother was found safe inside the apartment.