Detectives investigating the murder of a woman who was stabbed to death have appealed for two cyclists seen nearby to come forward.
The man and woman were seen cycling close to where Saudi Arabian student Nahid Almanea, 31, was murdered as she walked along a quiet footpath in Colchester, Essex.
It is thought they may have seen Ms Almanea after she was stabbed 16 times and left to die last Tuesday.
The pair, both believed to be in their 20s, were spotted on Salary Brook Trail heading towards the Greenstead estate at 10.45am on Tuesday, June 17.
The man is described as having olive skin, dark hair and is tall and slim, while the woman has long dark hair and was wearing a "flowing pattern tiered shirt".
Detective Chief Superintendent Steve Worron said: "I would appeal for these witnesses to come forward and help us with the investigation into Nahid's murder.
"They may have seen Nahid before she was attacked and they may have even seen her killer.
"I would also urge anyone who may know who these people are to contact us and tell us who they are.
"Please do get in touch with us. Any information they have no matter how small could help us."
More than 100 police officers from Essex, Kent and the Metropolitan Police are involved in the investigation into Ms Almanea's brutal killing, as well as profilers from the National Crime Agency.
Officers are yet to find the murder weapon and are keeping an "open mind" about possible links between Ms Almanea's death and that of James Attfield in Colchester two months ago.
Mr Attfield, 33, was stabbed 102 times on his arms, hands, back, neck and head in what police described as a "senseless and frenzied" attack.
Mr Worron has said that police do not have evidence that the killings are linked or that a serial killer is involved.
Detectives earlier said they were looking into the possibility that she was targeted because of her Muslim dress.
Officers yesterday drained a fishing pond and carried out an "intensive fingertip search" of the area close to where Ms Almanea was killed.
Police have already appealed for information about two men seen near the scene on the day of the attack.
The first was seen wearing a "distinctive" beige-coloured jacket while walking along the Salary Brook Trail around the time of the attack.
He is described as being aged from his late teens to 30, tanned and of average build with thick, black hair in a two-to-three-inch "mop style on top".
He was walking towards the Greenstead estate between 10.20am and 10.40am.
The second man is described as white, aged between 18 and 25, with a medium build and dark hair. Police said he was seen running up Hewes Close at around 10.56am.
He was wearing a long-sleeved, plain "London Bus red" hooded top and dark trousers.
Police have also previously appealed for help to track down a man who tried to attack a jogger less than a mile from where Ms Almanea was killed.
The white man, thought to be in his early 20s, around 5ft 7in and of medium build with a narrow face and possibly fair hair, tried to attack the woman in Peache Road, Colchester, at around 10pm.