Detectives investigating a series of linked knife-point robberies in the areas around the River Lea have identified four further offences they believe have been carried out by the suspects.
A total of eight incidents have taken place over a five day period from the beginning of this month, including four offences in one hour.
Detective Inspector Paul Ridley of Hackney CID is leading the investigation.
DI Ridley said: "Following a thorough review of robbery offences in neighbouring boroughs that the River Lea passes, including the actions of the suspects involved, we are now linking eight robbery offences.
"Four of the crimes occurred in under an hour, in a spree spanning Hackney, Tottenham and Waltham Forest, demonstrating the brazen nature of these robbers.
"In some offences, the suspects have used unnecessary threats and violence, attacking victims after they had handed over property.
"There have been increased patrols in the affected boroughs and activity has taken place to reassure the community, including warning local residents, many who have boats moored on the river. Officers in the affected boroughs have been briefed and will immediately respond to information received.
"I cannot discount that there may be other victims who have yet to contact police - I would urge them to come forward and provide us with any information they have; this may prove vital to our investigation."
The first offence happened at 22:15hrs on Tuesday, 1 August. A 31-year-old man entered the canal towpath outside of the Crescent Rowing Club on Spring Hill. He was riding his bicycle when he was approached by four black men, aged between 18 and 23 years of age, who were also riding mountain bikes. All of the men had their faces covered with scarves and had their hoods up. They blocked the victim's path and demanded his property before rifling through his pockets and repeatedly punching him in the face. They stole his phone and wallet.
The men demanded the PIN number for his bank card and threatened to stab him. The suspects then cycled north. The victim made his way to the nearby Anchor and Hope pub where he raised the alarm.
Within a few minutes of this robbery, a second man, aged 39, was approached by a group of men as he rode his bicycle near the river path at High Hill Ferry, E5. The suspects, who are described as black, pushed him off his cycle before punching and kicking him as he lay on the ground.
They stole a bank card, a watch, a silver crucifix necklace and his house keys. The victim, who sustained a leg injury in the assault, fled the scene and flagged down a passer-by who contacted police.
At 23:30hrs the following day, Wednesday, 2 August, three men, aged in their early 20s, were walking close to the Springfield Marina, E5. They were approached by three black suspects, aged in their late teens to early 20s, riding bikes.
The victims were all assaulted; one of them had a large black handled kitchen knife held to his throat. Their phone and bank cards were stolen.
The following day, Thursday 3, August at 23:40hrs a 32-year-old man was riding his bike along the River Lea canal towpath on the exit towards Yarmouth Crescent, N17. He noticed five males in front of him. All of them were on bikes. As the victim approached them, passing under a bridge, one of the males manoeuvred towards him, grabbing the handles of his bike and pulled it leading to the victim falling to the floor. The suspects, all described as black and aged between 16 and 20, pulled him into the undergrowth. A masked man then punched him in the face. The robbers demanded his property. The victim then began raising his voice which seemingly spooked the suspects who made off with the victim's distinctive yellow AA BSA Voodoo Bizango mountain bike.
The next offence occurred at 00:10hrs on Friday, 4 August as the 39-year-old victim was riding close to the Crescent Rowing Club. He was approached by a group of black men, again on bikes. They initially allowed him to pass as he crossed the bridge near to the rowing club. The masked men chased him but fled empty-handed towards Haringey.
Minutes later, at 00:21 hrs, a 30-year-old man was walking along Coppermill Lane, entering a park just before crossing the bridge over the river heading towards Spring Hill, E5. He noticed a black male behind a park bench who appeared to be hiding. The victim, who was wearing his headphones at the time, was approached by the male who attempted to grab his phone. The victim threw his handset in nearby undergrowth in a bid to protect it. This was then retrieved by a second suspect. A third male then assaulted him before a fourth male stole his wallet and demanded the PIN number. The victim was able to escape but observed the suspects approaching again so he hid in the undergrowth to evade them. They made off with his I phone 5, debit card and wallet.
He described the suspects as a group of black males, aged 16-19 years of age and between 5ft 11inches and 6ft 2inches tall - all were wearing balaclavas. One of the males had a fur hood liner in his jacket and another was seen to flee on an orange coloured mountain bike.
At 00:26hrs a 26-year-old male and 25-year-old female were walking along the canal towpath near to Yarmouth Crescent, N17. Without warning they were approached by three men who immediately demanded property. The male victim, to prevent the female from being harmed, urged her to run away. One of the suspects attempted to rip the handbag out of her hand. Fortunately she was able to scramble to nearby undergrowth where she took cover. The male victim was punched in the face and pushed to the floor by all the suspects. They rifled through his pockets, stealing his mobile phone and wallet.
Police nearby heard the victims' screams and ran to investigate. The male victim pointed out the direction the attackers had fled and they could be seen cycling away in a southbound direction towards Hackney.
The final offence occurred at 22:25hrs on Saturday, 5 August when a 28-year old man was targeted by the suspects whilst he was walking along the canal towpath by Craven Walk, N16. He was approached by three males on pedal cycles. The first suspect got off his bike and approached the victim demanding to know what was in his pockets. The victim, in fear of being robbed, placed his hands over his trouser pockets to demonstrate that he did not have any possessions. The men then fled empty-handed, cycling northbound along the towpath.
One of the suspects is described as a white male, 5ft 10inches tall, aged in his late 20s and wearing dark clothing. He was of stocky build and was wearing a face mask that covered most of his face.
Anyone with information is asked to contact Hackney CID via 101 or via Twitter @MetCC quoting operation name 'Glanford'.
To give information anonymously call Crimestoppers on 0800 555 111 or visit crimestoppers-uk.org
Crime prevention advice, including tips on personal safety, can be found on the Met's website.