Honolulu police are investigating a string of alleged robberies by a group of male suspects at Ala Moana Center and surrounding areas.

At least three alleged robberies occurred within a span of three hours Sunday afternoon and fourth robbery occurred Monday afternoon.

Police said a juvenile male was waiting for his food order at the Makai Market Food Court at Ala Moana Center at about 3 p.m. Sunday when two suspects approached him, demanded money and threatened to stab him. The pair fled with money taken from the victim.

A couple hours later, a 15-year-old boy and another male suspect approached a 20-year-old man near Planet Fitness at about 5:10 p.m. and demanded his property while one of the suspects brandished a machete, police said.

The suspects fled the scene before police arrived. Police said nothing was taken from the victim.

Within the hour, a third robbery occurred in the area of Piikoi and Kona streets. Police said four juvenile males approached a 52-year-old man, assaulted him and took his wallet at about 5:50 p.m.

The next day, a male teenager approached a 17-year-old boy at Ala Moana Center and allegedly threatened to use force in an attempt to take his personal property at about 3:30 p.m. Police said nothing was taken from the victim and no injuries were reported.

Prosecutors have charged the 15-year-old boy with second-degree robbery in connection with Monday’s robbery case. His name was not released because he is a minor.

Police noted the 15-year-old is linked to the robberies that occurred in the Ala Moana area.

An investigation into the robberies is ongoing.