“Smash-and-grab” thieves have hit at least 29 business from Annapolis to Landover to Gaithersburg during the past three weeks in quick nighttime strikes — smashing through glass doors, looking for cash and dashing out, according to police.

Detectives say they believe that at least 20 of the break-ins are connected.

“They were in and out of these places pretty quickly,” said Capt. Jim Daly, a Montgomery County police spokesman, describing nine of the crimes in the county on Tuesday night.

“It’s pretty brazen,” added Capt. Jimmy Simms, a commander for Prince George’s County police.

All of the businesses appeared to have been unoccupied, and no injuries have been reported. But police stressed that burglaries can turn dangerous.

Prince George's County police released photos from surveillance cameras they say show a man suspected of burglarizing fast food restaurants, as well as the car the alleged burglars used. (Prince George's County police)

“There’s always a chance of a confrontation,” Daly said.

The thieves seem to be going for cash — grabbing it from registers and even yanking out entire register trays and fleeing with them. The amount that has been stolen is unclear, but authorities said it is substantial.

The break-ins began about 4 a.m. Nov. 22 at Jerry’s Subs and Pizza in the 900 block of Bay Ridge Road in Annapolis. Someone broke through the glass door and took cash register drawers, according to Annapolis police.

About 42 hours later — the night of Nov. 23 — four Annapolis business were targeted within 31 minutes. A thief or thieves broke into Insane Car Audio and outlets of McCormick Paints, Dunkin’ Donuts and Subway.

Several days later, in Prince George’s, a thief or thieves struck 15 times starting about 12:30 a.m. Nov. 29 in a string of smash-and-grabs notable for their proximity. Thirteen of those businesses — including another Subway and a Bojangles’ Famous Chicken ’n Biscuits — sit along a two-mile stretch of Annapolis Road.

The owner of Pizza Oven in Prince George’s, also targeted that night, said thieves there made off with only about $22. But it cost him more than $450 to replace broken glass, clean up the store and replace a cash-register tray.

The expenses hurt, particularly during the holidays, said the owner, who requested anonymity because he feared retribution.

“It makes me think about closing the store after 56 years in business,” said Pizza Oven’s owner, who added that his restaurant had never been burglarized before. “It really is a heartbreak.”

The detective investigating the Annapolis break-ins has talked to his counterparts in Prince George’s and found similarities. “We believe the Prince George’s and Annapolis smash-and-grab burglaries are related,” said Cpl. Amy Miguez, an Annapolis police spokeswoman.

Daly, the Montgomery police spokesman, said detectives there are working to determine whether the crimes were connected to those in the other jurisdictions.

Police in Annapolis said break-ins there may have been the work of a man wearing a green or blue plaid hooded jacket, yellow-and-blue work gloves, light-colored pants and tan work boots. Police said that a green or blue minivan with silver trim was seen near the crime scenes.

Prince George’s police released surveillance photos of a suspect holding a tray of cash from a register, along with pictures of what they think is a getaway car. Detectives say they think the thief had an accomplice.

The smash-and-grabs, reported earlier by WJLA (Channel 7), seemed to stop for about 10 days. Then, on Tuesday night, alarms were triggered by bashed-in windows in Montgomery. Shortly before midnight, officers from the Gaithersburg force were called to Lindt, a chocolate retailer in the Rio shopping area near the Interstate 270-370 interchange. As they were heading there, an alarm activated at a nearby Corner Bakery.

Meanwhile, just two miles away, county police were called to break-ins at three businesses along North Frederick Road: Express Pharmacy, Dunkin’ Donuts and a BP gas station. They found a drawer from a cash register near one of the businesses, said Officer Dan Lane, a spokesman for Gaithersburg police.

That drawer was traced to the Taco Bar II restaurant — just a few blocks from Lindt and Corner Bakery. Officers reached the owner of Taco Bar II, Jose Valdivia, at his home, and he went to inspect the damage.

“They told me I was No. 3,” he said.

Valdivia said he is out $150 and must purchase a new cash register, which will be at least $600. But he struck a thankful tone, telling his wife that at least neither he nor any of his workers had a gun pointed at them.

“You know what,” he recalled telling her. “It’s just things. It’s not me.”

Valdivia emigrated from Mexico to California in 1979 and came to Maryland about 11 years later. He sold his first restaurant, Taco Bar, to his brother, and said that their businesses had never been broken into before Tuesday.

He said the thief or thieves walked by 11 cases of wine near the door they smashed through. “Didn’t touch any of it,” he said.