Muhammad Sharif told the BBC he saw his son Urfan Sharif, Sara’s father, soon after he arrived in the city of Jhelum, in the South Asian country, and said he had fled the UK out of “fear”.
Sara’s body was found at a property in Hammond Road, Woking, after police were called from Pakistan by her father on August 10 and a post-mortem examination later found she had suffered “multiple and extensive injuries” over a “sustained and extended” period of time.
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.
They travelled with five children aged between one and 13 years old, Surrey Police said.
Speaking to the BBC, her grandfather joined other family members in Pakistan to appeal for the three to return to the UK.
He said: “It was an accident, he didn’t tell me how it happened.”
Asked why they had fled, he said: “Because of fear.
“His daughter died and when you go under so much trauma, obviously you can’t think properly.”
He urged them to co-operate with the police inquiry, adding he had not seen them recently.
He said: “All I can say is that they should have faced the case. They should have stayed there and faced it instead.
“They will ultimately go back to the UK and face their case.”
Surrey Police are appealing for information to help them piece together a picture of Sara’s lifestyle prior to her death.
Sara’s mother, Olga Sharif, is being supported by specialist officers.
Surrey County Council previously told the PA news agency Sara was known to the local authority.
Authorities in Pakistan are searching for the trio and lawyers in the UK have said the nation’s government is unlikely to block an extradition request in connection to Sara’s death.
There is no formal extradition treaty between the UK and Pakistan but people have been returned from the Asian country before.