Police are investigating another robbery involving men with shotguns.

About 9:30 p.m. Thursday, two men, both carrying shotguns, entered Sonic at 4577 S. 4000 West and demanded money. Witnesses told police both men were either Polynesian or Hispanic and wore dark hoodies and bandanas over their faces. No shots were fired and no one was injured.

The robbery is the latest in a number of violent take-over style robberies throughout the valley in recent months.

On Saturday night, two restaurants were robbed within an hour of each other. The first was Chuck-a-Rama, 744 E. 400 South in Salt Lake. About 8:15 p.m., two men wearing dark hoodies, dark pants and covering their faces walked into the business and demanded money, said Salt Lake police detective Jared Wihongi. One man was armed with a long gun, possibly a shotgun, and the other had a handgun.

The two took money from the registers and left. No one was injured, and no shots were fired, Wihongi said.

About 35 minutes later, two men dressed similarly to those in the prior incident walked into Winger's in West Bountiful, near 500 West and 500 South, and robbed that business. Only a shotgun was seen, said West Bountiful Police Chief Randy Lloyd.

As the two men were driving away, the cook looked out the window and saw a flash, like one from a firearm. Detectives believe a small-caliber shotgun was fired at the restaurant, and the pellets bounced off the exterior, Lloyd said.

Investigators from several jurisdictions, including West Valley and Salt Lake, have been working closely to determine if they have one group of shotgun robbers hitting businesses around the valley or several groups, if the groups are all working together, and if the three people recently arrested in connection with the Family Dollar store homicide and robbery, 1145 S. Glendale Drive (1350 West) are tied in with any of the other incidents.

There have been other incidents in addition to the three robberies over the past week:

• On Feb. 14, Rancheritos, 1860 S. Redwood Road, was robbed by two men. Witnesses said one carried a sawed-off, pump shotgun. The suspects were described as Polynesian. One was about 6-foot-2 and the other 5-foot-5, according to witnesses. Both had stocky builds and wore hoodies and ski masks.

• On Feb. 9, three men wearing dark clothing fired a shot inside a Wendy's restaurant, 919 W. 2100 South, before robbing the cash registers. No one was injured.

• On Feb. 1, Molca Salsa, 2901 E. 3300 South, was robbed. Again, a shot was fired into the ceiling in that incident, but no one was injured. The suspects in that incident wore bandanas over their faces. They were described by witnesses as being either Hispanic or Polynesian. They were between 5-foot-8 and 5-foot-10 with stocky builds.

• In January, four men entered Factory 4 U, 3568 S. Redwood Road, one carrying a handgun and another a shotgun. One shot was fired into the ceiling before the store was robbed. The suspects in that incident were described as possibly being Polynesian. They wore black sweatshirts and bandanas over their faces.

Although the suspect descriptions have been similar in each incident, investigators do not have enough evidence to say they are related.

E-mail: preavy@desnews.com