Police Constable Andrew Harper died of 'multiple injuries', an investigation has found.
The newlywed officer was killed while responding to reports of a burglary on Thursday, around 11.30pm, near the Berkshire village of Sulhamstead.
In a press conference today, Detective Superintendent Ailsa Kent said police have been given an extra 36 hours to question ten suspects.
She said: "A post-mortem was carried out on Andrew’s body and the cause of death has been recorded as multiple injuries.
"The cause of death is consistent with our current belief that Andrew was caught between a vehicle and the road and then dragged for a distance."
She said the 10 people had been arrested at council-run caravan and mobile home site Four Houses Corner, which is about three miles from where PC Harper died.
It is understood that one of those arrested is a 13-year-old boy.
Following the tragic death of PC Harper Andy Fiddler, from Thames Valley Police Federation, said: "This is totally devastating news.
"All our thoughts - and the thoughts of the entire police family across the UK - are with the family, friends and close colleagues of Pc Andrew Harper who died last night.
"Police officers go to work each and every day to do their duty.
"We are courageous, caring and compassionate. We confront danger on a daily basis.
"We know there is a risk when we put on the uniform but we do so as we are proud to protect the public.
"Sadly on very rare and horrendous occasions a colleague makes the ultimate sacrifice. We will ensure that heroism is never forgotten."
