Image caption PC Andrew Harper was killed in Berkshire on Thursday

Detectives investigating the death of a police officer have said he died of "multiple injuries", as they were given more time to question 10 suspects.

PC Andrew Harper, 28, was responding to a burglary report on Thursday in Sulhamstead, Berkshire, when he was dragged along the road by a vehicle.

Ten males aged between 13 and 30 have been arrested on suspicion of murder.

Thames Valley Police said on Saturday it had been granted an extra 36 hours to question the suspects.

PC Harper, who got married four weeks ago, was killed on the A4 Bath Road.

Det Supt Ailsa Kent told a press conference: "A post-mortem was carried out on Andrew's body and the cause of death has been recorded as multiple injuries.

"[That] is consistent with our current belief that Andrew was caught between a vehicle and the road and then dragged for a distance."

Image copyright PA Media Image caption Police officers have been at a caravan site near to the scene where PC Harper was killed

Det Supt Kent said it remained unclear how PC Harper "came to be out of his vehicle and then caught under the suspect vehicle".

She said the 10 boys and men had been arrested at council-run caravan and mobile home site, Four Houses Corner, about three miles from where PC Harper died.

Officers are carrying out house-to-house inquiries, reviewing CCTV footage, interviewing witnesses and conducting forensic examinations, Det Supt Kent added.

Forensics officers could be seen combing the area as police widened the cordon around the scene earlier.

Chief Constable John Campbell said the death of PC Harper had left the entire force "shocked and saddened".

Mr Campbell said the officer was a "highly regarded, popular member of the team" and his death was a "significant loss" to the force and also to his colleagues and friends.

Image copyright PA Media Image caption Tributes to PC Harper have been laid at the scene

A group of officers could be seen gathered around floral tributes reading messages to their fallen colleague.

One tribute, accompanied by an image of PC Harper smiling with a friend, said: "Harps, I am truly gutted. A great cop, a great man, a great friend.

"There will always be a part of my heart missing now. RIP mate, love you. Chef, Sarah and Harry."

Another read: "Such a shocking, mindless, horrific act of brutality. This has been impossible for us to get our heads around.

"Pc Harper was a beautiful young soul. A brave man protecting us all and just doing his job."

PC Harper, who became a regular officer in 2011 after joining as a special constable a year earlier, had attended the reported break-in at about 23:30 BST with a fellow officer.

The officer on duty with PC Harper was not physically injured but is being given emotional support, Thames Valley Police said.

Image copyright PA Media Image caption One message described PC Harper as "Thames Valley's finest"

Deputy Police and Crime Commissioner, Matthew Barber, said he had received messages from members of the public whom PC Harper had helped.

A domestic violence victim told him the officer had given her the confidence to come forward about her abusive partner.

"He was clearly a man who, in his short time, touched many lives," Mr Barber added.

PC Harper's colleagues have been laying floral tributes at the scene, with one message describing the officer as "Thames Valley's finest".

Media playback is unsupported on your device Media caption "We are shocked and saddened by the death of our colleague"

Relatives of PC Harper have also paid tribute on social media to the "loveliest person that you will ever meet".

His grandmother Maureen Shrimpton wrote: "Just a really horrible day. Our grandson Andrew was killed last night while doing his police work.

"So proud of him. Our love goes to his lovely wife, mum and dad, brother and all of his family and friends."