ST. LOUIS - Authorities are investigating two armed carjackings and a business robbery that reportedly occurred Friday evening in St. Louis.

It's unclear if these crimes are connected, but the St. Louis Metropolitan Police Department is asking for the public's help with relevant information in all three cases.

No arrests have been reported from the two carjackings or business robbery as of Saturday morning.

Police first responded to a carjacking reported in the 3600 block of Herbert Street in St. Louis' Jeff-Vander-Lou neighborhood around 7:30 p.m.

Investigators say a 59-year-old man was sitting in his parked car when a man knocked on his window with a gun and ordered the man out of the car. The suspect took off in the car. Police later spotted the stolen vehicle while responding to a fire alarm in 400 block of Glasgow Avenue.

Then, around 8 p.m., police responded to a business robbery in the 3800 block of Gravois Avenue in St. Louis' Tower Grove South neighborhood.

Investigators say a suspect inside the store emerged from behind the business's coolers. The suspect pointed a gun at someone in the store and demanded money. The suspect reportedly took off with an undisclosed amount of cash from cash registers.

After that, around 10 p.m., police responded to a carjacking reported in the 1500 block of Menard Street in St. Louis' Benton Park neighborhood.

Investigators say a 23-year-old man and a 30-year-old woman were approached by a man wearing a black face mask and all black clothing. The suspect allegedly pointed a gun at the couple and demanded their belongings. The suspect then took off in the woman's car a short time later. Police later recovered the victim's cell phone and vehicle.

Anyone with relevant information in any of these investigations is urged to contact SLMPD at 314-444-2500 or CrimeStoppers at 866-371-TIPS (8477).