The body of Sara Sharif was found at a property on Hammond Road after police were called from Pakistan by her father, Urfan Sharif, on August 10.
Mr Sharif, 41, his partner, Beinash Batool, 29, and his brother, Faisal Malik, 28, are thought to have travelled to Islamabad on August 9 and are wanted for questioning.
In a statement to The Mirror, Rawalpindi Region police chief Khurram Ali said the force was trying its “level best” to find Mr Sharif, Ms Batool and Mr Malik, and was “close to locating them”.
Mr Ali said the force has interrogated the father, brother and uncle of Mr Sharif.
It comes as Surrey Police issued a new appeal for information on Thursday, two weeks after Sara was found.
Detectives are continuing to appeal for information to help them piece together a picture of Sara’s lifestyle prior to her death.
They widened the timescale of their investigation after the post-mortem examination revealed that Sara had suffered multiple and extensive injuries, likely to have been caused over a sustained and extended period of time.
Detective Superintendent Mark Chapman, from the Surrey Police and Sussex Police Major Crime Team, said: “It is now two weeks since Sara’s body was found and the impact of her tragic death continues to be felt deeply by the local and wider community, including our officers and staff.
“We would like to thank those people who have already come forward and reported information to us.
“However, we know that there will be lots of people in the Woking community and beyond who will have had contact with Sara who may not already have come forward, and we would encourage them to do so.
“Any information is better than no information – although you might think it’s insignificant, it might be vital to the investigation and in helping us to bring justice for Sara.”
If you have information, report this to the force online through the Major Incident Public Portal https://mipp.police.uk/operation/4523K72-PO2 or by calling 101, quoting Operation Unison.