HOUSTON -

The Houston Police Department is investigating three robberies reported in less than an hour in northwest Houston Monday night. At this point, it's unknown if the crimes are related.

Surveillance video from a Valero at 3400 W. Little York shows customers, including a child, running out of the store as three men ran inside with their faces covered. The men then jumped over the counter and made the clerk open the register.

After the robbery, the men left the same way they came in, hopping over the counter and running out of the store.

Just minutes before that robbery, another store was robbed at Highway 290 and Antoine. Police say three men had their faces covered with either ski masks or bandanas as they entered a Shell gas station. They were described as being between the ages of 20 and 25.

A third robbery was reported at China Doll Restaurant on Antoine near Tidwell. An employee told Local 2 two men came into the restaurant and pointed a gun at her as they demanded money.

No one was hurt in any of the robberies.