PC Andrew Harper’s father has said his “heart was so broken” for his family when he found out his son had been killed on duty.
Phil Harper said he was so proud of PC Harper’s brother Sean and sister Aimee for “being so dignified” during an “incredibly tough” time.
PC Harper, 28, suffered catastrophic injuries when he was dragged behind a getaway car in Berkshire last August.
His father has backed “Harper’s Law” launched by his son’s widow Lissie.
Mrs Harper, 29, has called for killers of emergency workers to face mandatory life sentences, “no ifs, no buts”.
On Friday, the attorney general Suella Braverman QC announced she had referred the sentences of PC Harper’s killers to the Court of Appeal because she considered them “unduly lenient”.
Speaking for the first time since his son’s killers were sentenced, Mr Harper said he was “so proud of Lissie for having the courage to take on this incredible task”.
“I’m also so proud of Sean and Aimee – Andrew’s brother and sister – for being so dignified throughout the last year, as it has been so incredibly tough for them too,” he added.
“Both have lost more than just a brother – he was a best friend as well, who would always take the time to give the best advice he could. My heart was so broken for them when they heard the terrible news.”
Mr Harper also paid tribute to his wife Karen for her “love and support”.
A trial at the Old Bailey heard how PC Harper had responded to reports of a quad bike theft with a colleague hours after their shift had ended on 15 August 2019.
As he attempted to apprehend one of the three suspects, his feet became entangled in a rope trailing behind a getaway car, which led to him being dragged to his death.
The driver of the car, 19-year-old Henry Long, and his passengers Albert Bowers and Jessie Cole, both 18, were convicted of manslaughter but cleared of murder.
Bowers and Cole have launched appeals against their convictions.
Their sentences prompted Mrs Harper and PC Harper’s mother Deborah Adlam to launch campaigns calling for tougher sentences for killers of emergency service workers.
Mrs Harper, from Wallingford, Oxfordshire, said her campaign, backed by the Police Federation of England and Wales, would “help fix” a “broken” justice system.
Mr Harper said there was a “need for Harper’s Law” and he hoped the public would “back and support Lissie’s campaign in memory of Andrew”.