Shoppers looked on as police swooped on Harrow town centre to deal with two lunchtime incidents.
Staff at New Look at St Ann's Road raised the alarm on Friday (06) to say they had noticed three possible shoplifters leaving the shop at 2.20pm.
Security guards at nearby Debenhams detained one female suspect but after she handed back the stolen items, she was released and the police did not get involved.
Half an hour later police officers were called to Station Road to reports of a disturbance involving a large group of men.
No further details were available but a Harrow Police spokesman told the Observer officers were "monitoring the situation and in attendance around Harrow Bus Station in College Road."