South Australian police have established a taskforce to investigate the death of a detective in the 1994 bombing of Adelaide's National Crime Authority office.
Detective Sergeant Geoffrey Bowen died when he opened a parcel bomb delivered to the NCA office in Waymouth Street in the CBD.
A lawyer, Peter Wallis, was seriously injured in the bombing.
Adelaide man Domenic Perre was arrested over Det Sgt Bowen's murder but charges were dropped six months later because of a lack of evidence.
Police are offering a $1 million reward for information leading to the conviction of the person responsible.
The taskforce has conducted a confidential review of the crime, and the subsequent investigation and judicial processes.
It is looking for witnesses who withheld or fabricated information in the past.
All anonymous callers who have contacted Crime Stoppers about the bombing have been asked to call again on Tuesday evening.
The bombing victims' families have expressed their gratitude at the renewed efforts to bring the person responsible to justice.
"My family is very happy that there is a renewed investigation and will not be commenting further at this time," Mr Bowen's widow Jane said.
Premier Jay Weatherill said the taskforce was welcome news.
"This has been, I suppose, one of those stains on South Australia," he told reporters.
"It's heartening to see that additional resources have been applied in this case."
