In the past six weeks, 11 chain coffee and sandwich shops have been hit by robberies in Minneapolis and the western suburbs.
It's forced Minneapolis police to issue guidance to businesses across the metro about how to respond in the event of a robbery.
Since Dec. 10, five Starbucks stores, four Subways, two Caribous and one Dunn Bros. outlet have been the target of early-morning robberies, according to a City of Minneapolis release.
They have been targeting chain stores – coffee shops before 7:30 a.m. and Subway before 10:30 a.m. – with independent businesses not affected.
That said, police say anyone who owns or uses a coffee or sandwich shop, whether chain or independent, should "be aware."
Police have released some images of suspects, but it's not clear if the culprits are the same in each robberyinstance.
Anyone with information about the robberies or the suspects pictured, contact the Minneapolis Police Department Robbery Unit at 612-673-2941 and ask for investigator Sgt. Mike Heyer.
Advice to shop workers
Shop workers are urged to remain calm, cooperate with robbers and don't resist.
"Safely do what the robber asks but don't volunteer to do anything else," the advice says.
They want workers to take mental notes of as many details about the robber as they safely can, and if possible give them marked money without alerting them.
"While waiting for police, write down what you remember about the incident; description of robber, what was said, weapons, any other information," the police advice says. "Do not discuss what you remember with anyone else until after you have spoken to the police, as you may inadvertently muddle your memory."
Staff are also encouraged to remove window obstructions and call 911 whenever they see something suspicious as a way of preventing a robbery before it happens.
Staff should give every customer "a friendly greeting" and look directly at them. This human contact may deter the robber, police say.
The 11 robbed stores
Here's a list of the stores robbed over the past six weeks.
12/10/2016, 8:30 am, 3541 Cedar Ave S, Minneapolis.
12/10/2016, 9:40 am, 5317 Lyndale Ave S, Minneapolis.
12/15/2016, 7 am, 4741 Hiawatha Ave S, Minneapolis.
12/19/2016, 9:13 am, 5327 16th St W, St Louis Park.
12/10/2016, 6:52 am, 2515 Riverside Ave, Minneapolis.
12/12/2016, 5:39 am, 2000 Nicollet Ave S, Minneapolis.
12/21/2016, 5:37 am, 7610 Lyndale Ave S #800, Richfield.
1/9/2017, 6:20 am, 1820 Hwy 36 W, Roseville.
1/19/2017, 5:35 am, 4201 Minnetonka Blvd, St Louis Park.
1/22/2017, 7:33 am, 5008 Xerxes Ave S, Minneapolis.
12/24/2016, 6:52 am, 2218 County Rd D, Roseville.
12/24/2016, 7:18 am, 4745 Cedar Ave S, Minneapolis