He's "scrawny," wears a hood or some type of mask over part of his face, and displays an object wrapped in a plastic bag before demanding money.
He targets small businesses, often staffed by just one or two employees, mostly at night, after darkness falls.
A man matching this description has robbed or attempted to rob at least nine businesses in Lake County, including sandwich shops, a gas station, a candy store, a smoothie shop and a health food store, police said. The businesses are in Highland, Munster, St. John and Griffith.
As news of the robberies has spread, police have heard from concerned business owners, Highland police Cmdr. John Banasiak said.
"We want them to be aware of it, so they can be vigilant," he said.
'Not worth taking the risk'
The suspect appears to be targeting businesses where there's less chance of resistance, where he's dealing with just one or two employees face to face, Banasiak said.
In businesses with a single employee, a bell or system to alert the employee when someone enters is recommended, he said. If multiple employees are working, they should work together to pay attention and avoid working apart for too long, he said.
Most cases have been reported at night, so employees should be vigilant, especially after dark. Call 911 immediately to report anything suspicious, police said.
It's unclear whether the object wrapped in a plastic bag is a gun, though the man uses it to imply he has a weapon.
Employees should assume it is a gun and not hesitate to comply with demands, Banasiak said.
"It's not worth taking the risk over property that can be replaced," he said.
Most businesses are insured in case of a robbery, he said.
Police: Report suspicious activity
The man recently attempted to rob Baum's Natural Foods in the 1800 block of West 45th Street in Munster.
Lauren Bridgmon, a longtime employee, wasn't working the night of the Nov. 7 robbery attempt but said Munster police returned the following day to make sure employees felt safe.
Police have stopped by several more times since then, and they typically check in as winter approaches each year to encourage businesses to report anything suspicious, she said.
"It is on citizens in general to be aware and report any suspicious activity," she said.
Bridgmon said it's a good thing news is getting out about the robberies. Increased awareness means small business owners can take precautions, perhaps by adding employees at night, she said.
Police in Lake County reported no new cases so far this week since a robbery Sunday at Fannie May, 3949 Ridge Road, in Highland. In that case, a K-9 tracked the man to the 3900 block of Klough Street. Investigators suspect the man may have gotten into a waiting vehicle at that point, Banasiak said.
The man has been described as white or light-skinned Hispanic and 5 foot, 5 inches tall to 5-foot-7, with a thin or scrawny build and small stature. He often covers at least part of his mouth with a mask, police said.
In Highland, police are conducting "extreme extra patrols" that include patrol officers and detectives, Banasiak said. Griffith police also have been patrolling more often around vulnerable businesses, Cmdr. Keith Martin said.
The goal is to be ready at the first sign of trouble, Banasiak said.
"As soon as it comes out, we're going to be going there" and surrounding areas in hopes of gathering information that could lead to an arrest, he said.
In St. John, where Smoothie King in the 8200 block of Wicker Avenue was also robbed Nov. 7, Police Chief James Kveton recommends all business employees stay aware of their surroundings.
"Even with it being cold, if someone comes into a store completely covered with hat, gloves, hood, sunglasses and covered face I would be very suspicious of the person," he said. "I would recommend not working alone, always having at least two employees working and each keeping an eye on the other."
Kveton said sometimes giving a customer attention such as giving eye contact or acknowledging them by voice as soon as they walk in the door is a deterrent because the person realizes they have been noticed.
"If you see someone suspicious call 911 and have an officer check it out," Kveton said. "I would rather have an officer come by and check out a person that is innocent than not get the call of a possible suspect. When all else fails if you are confronted by a criminal, don't try to be a hero, comply with the offender's requests. Property can be replaced but you can't."
Kveton said if that happens then be a good witness. Try to remember things about the offender like height, weight, hair color, gender, race, age, clothing and anything unusual about him or her like a limp, accent, scars, tattoos and anything that could help identify them after they leave.
"And let them leave," he said. "You are safer with them out of the store."
Despite no new recent reports in Lake County, Michigan City police in neighboring LaPorte County reported at about 7:44 a.m. Monday someone robbed the Subway restaurant at 216 W. U.S. 20.
The man came into the store wearing a black Nike hooded sweatshirt with a gray stripe under the arms and black jogging pants with a gray stripe running down the legs, according to Michigan City police. He implied he had a weapon and wore a camouflage mask over his head.
While police said it's too early to say definitively if the robbery is connected to those occurring in Lake County, Lt. Steve Westphal said they are exploring that possibility as their investigation continues.
Anyone with information is asked to contact Michigan City Detective Cpl. Tim Baker at 219-874-3221 ext. 1075.
Times staff writers Rob Earnshaw and Lauren Cross contributed to this report.