Thunder Bay police are investigating two back-to-back convenience store robberies that happened in the city's north side on Friday night.  

In a news release, police said a weapon was used to rob a convenience store on River Street, then another convenience store on North Cumberland Street was robbed three minutes later. 

Police said the suspects drove off and then were involved in a motor vehicle collision. 

They arrested a 17-year-old boy, but the other suspects — a male and two females — fled the scene. 

Police said they found the weapon involved in the robberies and that no one was injured. 

They said the robberies happened during a very busy night, as police responded to nearly 50 calls in less than eight hours. 

Anyone with information regarding the two robberies is asked to contact Thunder Bay Police or Thunder Bay District Crime Stoppers. 

CBC News contacted Thunder Bay Police on Sunday morning for further details, but they were unable to provide any specifics about the weapon or which stores were robbed.