NHK has learned that police in Tokyo have arrested seven individuals linked to the theft last year of cash worth more than 270,000 dollars.

The individuals may have been recruited through social media by "Luffy," a person thought be in the Philippines who may have directed a recent series of crimes in Tokyo and elsewhere.

Sources close to the investigation say the group allegedly forced themselves into a home in Inagi City last October, and injured a female resident.

They made off with a safe that contained about 35 million yen in cash and a gold bar.

The suspects disguised themselves as parcel deliverers, and bound the victim with adhesive tape.

Three of the seven suspects had been arrested and charged in connection with an attempted robbery in Iwakuni City, in the western prefecture of Yamaguchi, last November.

Police are investigating possible links between the suspects and the robbery-murder of a 90-year-old woman this month in Tokyo's Komae City, a robbery-assault in Tokyo's Nakano Ward last month and an attempted robbery-murder last month in Hiroshima City, western Japan.