The Union Police Department took three reports of counterfeit cash being passed in Union from Friday through Sunday, Jan. 5-7.
While all three are likely related, police said serial numbers in two of the incidents match.
Capt. Kyle Kitcher said the department is investigating all three reports, which includes reviewing incidents reported in the past.
According to reports, the first incident occurred Friday, Jan. 5, at Midwest Petroleum. Officers seized a counterfeit $10 bill.
The second incident was reported Jan. 7 after the victim attempted to use cash he received from selling his X-Box video game system online. The suspect was located and admitted to purchasing the video game system, but said he was unaware that the cash was not real.
Later that night, a Fas-Trip employee recognized that cash was counterfeit and provided police with a license plate number, which led police to an apartment on Falcon Drive in Union.
According to police, when officers made contact with the suspect they smelled burning marijuana and were granted permission to search the residence.
During the search, additional counterfeit cash was located, as well as drugs and paraphernalia. Four people were arrested and may face charges for passing the bills and/or drug-related offenses.
The suspects are from the Union, St. Clair and Warrenton areas.