A 16-year-old boy was arrested within the Hackney Space on June 22 as a part of the investigation.
One other 16-year-old boy was arrested on June 17, he has since been launched on bail.
A 18-year-old man was additionally arrested on June 7 however later launched on bail pending additional enquiries.
In lots of the incidents, lone girls had been strolling or jogging after they have been approached by a male on a bicycle.
The male then proceeded to seize them from behind or contact their genitals or breasts earlier than making inappropriate feedback and leaving.
Detectives are persevering with to enchantment for info relating to the linked-series of assaults and final week launched an E-fit of a male they had been working to establish.
Detective Superintendent Mike Hamer, from the Central East Fundamental Command Unit, mentioned: “We have now now made three arrests in reference to these sexual assaults and our investigation continues at tempo.
“I perceive these assaults have induced appreciable concern among the many group, however we’ve a devoted workforce of officers working across the clock and finishing up a variety of enquiries to convey the perpetrator to justice.
“This investigation is a precedence for my workforce and we’re taking it extraordinarily critically.
“We even have an elevated police presence within the space, and officers are talking with members of the group to supply reassurance. Anybody with any considerations can communicate to those officers or name 101.
“We’re persevering with to enchantment for the general public’s assist and we’d ask that anybody with info which may assist our investigation, or any victims who haven’t but come ahead, to contact police as a matter of urgency.”
Anybody who has info that would assist police ought to name 101 or Tweet @MetCC and quote CAD 2905/22JUN
To stay 100 per cent nameless, contact the unbiased charity Crimestoppers on 0800 555 111 or on-line at crimestoppers-uk.org