YOKOHAMA (Kyodo) -- Police on Saturday arrested a 22-year-old man for allegedly killing an elderly man and stealing cash in Yokohama near Tokyo earlier this week.

The suspect, Mazuki Takarada, admitted to the allegations, telling police, "There were three perpetrators including me," in the robbery case, they said.

Hiroharu Goto, 75, was found dead Wednesday with his hands and legs tied at his home in Yokohama and signs of having been beaten, according to the police. His house was ransacked and around 200,000 yen ($1,300) had been stolen.

The police believe multiple suspects were involved in the robbery-murder incident.

The incident is among a spate of robberies in and around Tokyo, with the suspects believed to have been recruited and instructed to carry out their alleged crimes via social media.

The police forces of Tokyo and its surrounding prefectures of Chiba, Saitama and Kanagawa on Friday set up a joint investigation headquarters in response to the robberies that have targeted private homes since August, with similar tactics being employed.