(KMOV) -- Police have increased patrols following a rash of hold-ups taking place within a matter of hours in the Central West End.
Police say detectives are gathering surveillance footage and talking to possible witnesses to the three reported incidents between 9 p.m. and 2 a.m.
Authorities say in all three cases, a male suspect flashed a gun and demanded cash and cell phones from the victims.
The first robbery took place on the 4400 block of Olive at 9:20 p.m. with a second incident reported on the 4400 block of McPherson within a few minutes of the last.
A third robbery was reported on the 4900 block of McPherson at 2:11 a.m., where a 29-year-old woman and a 25-year-old man were robbed of a wallet and purse before the suspects allegedly struck both victims over the head with a firearm.
The victims sustained minor injuries and refused medical treatment on the scene.
"Our victim was struck with a firearm in the third case where there was no such violence in the first two, so that always take our concern to a new level when violence like that accompanies a crime of this nature,” said Major Michael Caruso of the St. Louis Metropolitan Police Department.
The suspect reported in each case was described as being a black male, 20-25-years-old with a dark complexion, thin build, wearing red stocking cap, black jacket and blue jeans.
Major Caruso said investigators are working to determine in the cases are connected. Increased patrols are scheduled for the area through the holiday season.
The investigation into these robberies is ongoing.