Detectives investigating up to 25 sexual assaults they believe to be linked across south-east London are not ruling out the possiblty the attacker's behaviour will escalate.
Police have released new CCTV footage of a man they would like to speak to in connection with the attacks which began last year.
The string of assaults against women and schoolgirls as young as eight began in October 2016. Seventeen of the 25 vitims are children.
The attacks have mainly been in the Lewisham and Greenwich boroughs, but have spread as far as Bromley, Bexley and Southwark.
Incidents have typically happened during rush hour periods, between 7am to 9am and 4pm to 6pm.
Police believe the first attack was on October 16, 2016, when a 13-year-old girl was sexually assaulted in Foxfield Road, Orpington around 9.15am.
Since then, police have received reports about similar offences that may have been committed by the same suspect.
The last reported assault was committed on November 22 when a 15-year-old girl said she was sexually assaulted in Sandbourne Road, Brockley just after 8.30am.
From this incident, officers were able to recover CCTV footage showing a male that they would like to trace as part of their investigation.
He is described as a middle-aged white man aged in his 40s, with blue eyes.
Police have increased patrols in the areas where offences have been reported, and are working with nearby schools to reassure pupils and parents.
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Detective Chief Inspector Andrew Furphy of Lewisham police, leading the investigation, told News Shopper: "We believe the first attack was in October last year by I am keeping an open mind on whether there may have been earlier ones.
"It is very hard for me to comment, but again we are keeping an open mind that if he is not caught his behaviour might escalate. We are not ruling that out.
"It is traumatic for the victims many of whom are schoolgirls but it is imperative we are told.
"They might not realise they are victims, we need parents and teachers to be alert and get in touch with us as soon as possible.
"We have increased patrols and are working in partnership with schools to reassure the community."
The victims have provided very similar descriptions of the attacker - a white man aged between 40 and 50.
DCI Furphey said: "It is also notable that none of these offences have taken place over a weekend and many of them have been committed during the morning and evening rush hours.
"Our officers have been working tirelessly to apprehend the suspect, but we need the public's help. CCTV shows footage of a male that we would like to speak to who we believe may be able to assist our investigation. If this is you or if you know who this person is, please contact us.
"We are also aware that there might be further victims who have not yet spoken to police; if you are a victim, or know someone who has been a victim of a sexual assault, I can assure you your information will be treated with the strict confidence and sensitivity. We also have access to specialist support."
Anyone with information should contact the incident room on 0208 284 8346 or call 101 or tweet @MetCC. Alternatively, you can contact Crimestoppers on 0800 555 111.
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