Xi Zhou and Zhen Xing Yang were found dead at 8 Croydon Road shortly after 4.30pm on Saturday, August 9, and police are now keen to trace the individuals seen by a passer-by shortly after one of the victims was last seen alive.

As previously revealed, police have a CCTV image of Miss Zhou near her home on Thursday, August 7, at around 4pm.

Officers also know that Mr Yang made a final call from his mobile phone at 12.42am earlier the same day.

A female witness who was walking past Croydon Road at 5pm on Thursday, August 7, less than one hour after Miss Zhou was last seen alive, saw three people standing at the front gate to number 8.

Two of the individuals had their backs to her and she could not see what they looked like or whether they were men or women.

However, they were a similar height to the third individual, who she got a good look at.

The witness describes the third individual as a man of Chinese appearance in his late 20s or early 30s, 5ft 4in tall, with short dark hair and of plump build.

He was wearing silver rimmed glasses, light blue jeans, a short-sleeved white and light blue football-style top, possibly with a logo on the front in the centre.

Northumbria Police Detective Superintendent Steve Wade, senior investigating officer, said: "These three individuals were seen at the front gate of 8 Croydon Road very close to the time that Xi Zhou arrived home from work on Thursday, August 7.

"It is important for us to trace these three and speak to them as they may have important information.

"I am asking that anyone who has seen these three, or who has any information about them, to contact my officers at once."

As a result of a previous appeal to the Chinese community through the Chinese media in London last week, police have traced a very good friend of Miss Zhou to London where officers from Northumbria Police are travelling to speak with her to gain a better understanding of Miss Zhou's lifestyle.

Police have also finished their forensic examination of the crime scene, however, it will be retained by police in case any further examination is required.

Anyone with information about the murders or the two victims, should contact Northumbria Police on 08456 043043.

Northumbria Police has created a stand alone e-mail address where people can leave messages in their chosen language at northumbriapolice@ymail.com

There is also a voice message service in Mandarin and Cantonese, where people can leave a message in their chosen language available on (0191) 221 8200.