Police rushed to Hillside Avenue following a report a woman had been picked up by a man and put into a silver car - possibly a Ford-Fiesta - at around 9pm on Tuesday (October 6).
A woman, possibly carrying a baby, was also believed to be with the pair.
Officers say they have had no reports from any victim and "it isn’t clear exactly what occurred", and they are now urging any witnesses to come forward to "establish whether any offences have actually taken place."
Det Sgt Stephen Craig, of Blackburn CID, said: "This incident came to us from a third party, so at the minute it isn’t clear what happened and we have had no complaints from anybody who may have been a victim.
"Did you see anyone acting suspiciously in the area around the time of the offence? Did you see a silver car being driven towards the scene or making off from the area?
"If you have any information that can help with our enquiries we would urge you to contact us as soon as possible."
Police say they are particularly keen for information about the silver car which was reportedly seen in the area at the same time.
Anyone with information has been urged to contact police by calling 101 or emailing [email protected], quoting log number 1456 of October 6.
Alternatively, independent charity Crimestoppers can be contacted anonymously on 0800 555 111 or via their website https://crimestoppers-uk.org/