Police in Berkshire have been given another 24 hours to question 10 male suspects over the death of a police officer last week.
PC Andrew Harper died when he was dragged under a vehicle and possibly hit by a police car after he was called out to a robbery on August 15.
Thames Valley Police arrested 10 people aged between 13 and 30 at a nearby caravan park.
The investigation continued over the weekend as police closed roads near the park and searched the area for evidence. Forensic officers also searched a black hatchback inside the caravan park.
The crime scene has become a memorial site for fellow officers to pay their respects.
One tribute 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.”
Officers said Pc Harper will be 'sorely missed' by the police community
A crowdfunding campaign has raised more than £146,000 for the family of PC Harper.
The Thames Valley Police Federation has led the campaign, and said it will “ensure that heroism is never forgotten”. PC Harper’s family will decide how the money will be used.
The Federation said: “Police officers all over Thames Valley and the rest of the UK 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.”
The crowdfunding campaign has exceeded its original target
PC Harper married his wife Lissie just four weeks ago and was due to go on his honeymoon in a few days.
His father Philip said the family are “absolutely devastated” and “in a bad place”.