The bomber who killed Rosemary Nelson planted the device within hours of the solicitor returning from a family holiday in Donegal, the inquiry into her murder heard yesterday.
At the opening of full hearings into the Lurgan lawyer's death, Rory Phillips QC said the inquiry would examine "very troubling suggestions" about the 1999 murder.
Those included security force activity around the family home in Ashgrove Grange the night before the killing, when Mrs Nelson had returned from a short caravan break with her husband, Paul, her daughter and her friend, the then Sinn Fein MLA Dara O'Hagan.
Mr Phillips, the counsel for the inquiry, said the Nelson family drove back from Donegal in the car which would explode the next day as Mrs Nelson went to work - meaning the bomber had placed the device underneath it shortly after they returned.
Mrs Nelson, a 40-year-old mother of three, died when a bomb exploded in her car as she drove to work from her home in March 1999.
Her widower and other family members - including her mother, brothers and sister - attended the opening hearing at the Interpoint Centre in Belfast.
Mr Phillips told the hearing in Belfast that the allegations the inquiry would examine include the possibility of "the state's involvement in the murder of one of the state's own citizens".
"The claims and counterclaims have had no public airing until now," he said.
"There has been no hearing. No public investigation of what happened has ever taken place.
"There have been no answers and no calling to account and nobody has been made answerable."
Mr Phillips said the attack on the solicitor "had an impact and an effect far beyond the confines of her home town", noting that President Bill Clinton, Prime Minister Tony Blair and Taoiseach Bertie Ahern condemned the murder in a joint statement.
The QC said it was "absolutely plain" that Mrs Nelson was the focus of hatred.
He said it was striking that the fact of her murder had been foretold " not least by her".
"What happened to Rosemary Nelson was, in a sense, no more than the dreadful fulfilment of death threats which she had spoken about privately and publicly in the months and years before her death," he said.
Mr Phillips said the inquiry will look into issues leading up to the murder - including the threats against her - and then examine the police investigation of the killing. He said a large amount of allegations about intimidation against Mrs Nelson involve police officers. The inquiry will look at how those allegations were handled by the RUC and NIO.
"When is a threat to life to be properly addressed as a complaint and only a complaint?" the QC asked.
He said the inquiry would look at what the police and NIO knew "about Rosemary Nelson, what was happening to her and about concerns that were being expressed about her personal safety".
The inquiry, which was established in 2005, cost £25m before the opening of full hearings.
The head of MI5 at the time of her murder will be among the witnesses called to give evidence. Mr Phillips said witness statements have been taken from 30 police officers up to the rank of assistant chief constable, 19 MI5 intelligence officers and eight senior army intelligence officers.