A 26-year-old security guard was found dead early Tuesday in Sayama, Saitama Prefecture, with a kitchen knife lodged in his back, police said.
Two coworkers found the blindfolded, bound body of Takeru Matsutani at around 4:15 a.m. at Sayama City Hall, they said.
Meanwhile, a security alarm at Asahi Bank's Shin-Sayama branch, about 3 km east of City Hall, was activated at around 4:20 a.m., according to police.
They said cash dispensers at the branch had been raided and that several tens of millions yen was missing.
Saitama Prefectural Police sources said they have set up a task force at the Sayama Police Station to investigate the death and any possible links with the theft.
While on duty at his security firm in nearby Kawagoe, Matsutani was dispatched to Sayama City Hall alone after its security alarm was activated at around 1 a.m., investigators said.
He last made contact with his coworkers at around 2 a.m., after which they went looking for him.
Investigators said they are looking into whether Matsutani was carrying a spare key for the bank branch when he left the office.