The Metropolitan Police Department is investigating the possibility that the murder this week of a 66-year-old tourist in Petworth could be linked to other attacks in the neighborhood, NBC4 reports.

Gary Dederichs, who was visiting from Denver, was found about 6 p.m. Tuesday in an alley in the 800 block of Emerson Street NW. Authorities said the cause of death was severe head trauma.

Now police are determining if there is any connection between Dederichs’ death and two more assault victims in the area who were hospitalized after suffering severe head trauma. A 53-year-old man was found on Georgia Avenue NW several hours after Dederichs and is currently hospitalized in critical condition. Police said he suffered trauma from a blunt impact to the head, NBC4 reports.

And about 8:40 p.m. Wednesday, a 37-year-old woman walking on 9th Street NW was struck in the head and was taken to a hospital in serious condition.

Police are now going door-to-door advising Petworth residents to stay alert. More unnerving still, is that it’s very possible the victims were attacked without provocation, MPD Chief Cathy Lanier tells NBC4.