Dr Libby Wilson was the first person to be arrested since the publication of new guidelines on assisted suicide and she accused the authorities of an "appalling waste of public money and police time and effort".
The retired doctor, 83, is a right-to-die campaigner who runs the organisation Friends at the End, which advises terminally ill people how to take their own lives, as well as helping to arrange trips to Dignitas, the Swiss clinic.
She was asked to attend Woking police station in Surrey yesterday morning and was arrested after disclosing that she gave "final tips" to Cari Loder, a 48-year-old multiple sclerosis sufferer who killed herself at her home in Surrey in June by inhaling a lethal dose of a gas she had ordered over the internet.
Last night, Dr Wilson, from Glasgow, said she had had nothing to do with the death of Ms Loder. She said she had only had two conversations with Ms Loder prior to her death.
She said: "The police were very polite and pleasant, but I just think it is an appalling waste of public money and police time and effort to investigate the death of a woman who wanted to die and had very good reason to die.
"I had nothing to do with the means of how she did it. I spoke to the lady and she phoned me twice, but that was the extent of my involvement."
At the time of Ms Loder's death, Dr Wilson said that she "wouldn't be surprised" if she faced questions over her involvement.
Back in June, she was reported as saying: "I spoke to Cari many times. She just wanted to make sure she had everything in order and to ask whether I had any final tips that might help. It's not my business to persuade people to not commit suicide."
In an interview published on Sunday, Dr Wilson said she suggested how Ms Loder might use the gas and recommended a "a few dummy runs" before going through with the suicide.
Dr Wilson, who travelled south over the weekend, became the first person to be arrested since Keir Starmer, the Director of Public Prosecutions, unveiled guidelines last week intended to clarify the law on assisted suicide.
The new laws make it less likely that people who help terminally ill patients die will face prosecution, unless they stand to gain financially.
In England and Wales, there is a law prohibiting assisting a suicide, which currently carries a maximum penalty of 14 years in prison. However, in Scotland there is no such law and individuals have previously been charged with culpable homicide.
Last week, Lord Advocate Elish Angiolini said there was no need for such guidelines in Scotland. However, independent MSP Margo MacDonald has introduced a bill into the Scottish Parliament advocating physician-assisted suicide.
Yesterday a spokesman for Surrey Police said: "An 83-year-old woman attended Woking police station this morning by appointment where she was arrested in connection with the death of Cari Loder at her home in Farncombe on 8 June this year. She has been released on police bail until 18 November."
Campaigning for the rights of terminally ill to choose death
DR LIBBY Wilson wrote in The Scotsman in June: "Is it right that the moral code of one group should be imposed on others who do not share it?"
As an 83-year-old retired GP, Dr Wilson is determined to fight to ensure that the terminally ill who wish to end their lives are legally allowed to do so.
As the founder of Friends at the End, she has helped arrange trips to Dignitas, the Swiss suicide clinic, including that of Elisabeth Rivers-Bulkeley, the prominent former stockbroker and socialite who killed herself in 2007.
She said at the time: "Elisabeth approached us and was quite happy to use our services."
She is also the co-author of A Hastened Death by Self-Denial of Food and Drink, which instructs people on how best to starve themselves to death, but admits that the process is "horrific" – one woman starved herself for 25 days before she died.
Dr Wilson said in a recent interview: "We are now getting contacted by, on average, three or four people a week, asking for information.
"In the past, we have been accused of leading people by the hand to commit suicide, but I can honestly say that I don't think I have ever suggested that someone use Dignitas."