Police are investigating two home invasion robberies in the quiet city of Piedmont that happened just minutes apart Monday morning.

Piedmont police said they received a call about a suspicious doorbell ring on Estates Drive Monday.

Ten minutes after police responded, four or five armed, masked robbers hit a house on the same block.

Police said the robbers carried a rifle and a semi-automatic handgun.

The suspects forced their way into the home, but the couple inside wasn't hurt.

A half hour later, across town, on Arroyo Avenue, armed robbers struck again.

That shot may have been a warning at the second home invasion, said the interim Piedmont police chief, Capt. Scott Wyatt.

Wyatt explained that the robbers forced their way inside. When the wife screamed, he said, someone punched her, then locked the husband downstairs, all while children slept.

As the robbers left, the wife followed the men out.

That's when the gunshot rang out and a bullet pierced the home's window.

"This one is very unusual, both in the type of crime and the time," Wyatt said.

Ben Aldson, a neighbor, opened his door to show dogs, which he said scared away the robbers from making his home the first house to be hit on Estates Drive Monday morning.

"My parents are like 'these people were all coming at us,' but the dogs were really loud so it must have scared them off," Aldson said.

Across the street, a neighbor said two weeks ago, a home burglary two houses down pushed her into buying an alarm system.

"I did not want to have a security system," the neighbor said. "I guess I have to have one now. It's really scary."

Police said Piedmont is a target because of its location.

"It's very easy for the bad guys to get in and out quickly," Wyatt said.

Piedmont police will be looking into whether these home invasions are tied to any in nearby Oakland.

Police said the getaway car was a silver or gray SUV, similar to a Suburban, that had front end damage and an African American woman may have been behind the wheel.

A jewelry box, computer monitor and some change were stolen from the first home and a computer, some video equipment and a safe were taken from the second house.

Piedmont had four home invasions last year and only twice that number of robberies.