Retired NHS worker escorted woman to assisted death at Dignitas
Retired NHS worker Sue Lawford spent 19 hours in custody and was investigated for six months for chaperoning a woman to her assisted death in Switzerland.
She went with wheelchair user Sharon Johnston, from Cardigan, Ceredigion, who was paralysed after a fall in her house, to the Dignitas clinic.
Ms Lawford, 70, from Cardiff, said police, who arrested her on returning from Switzerland, were "aggressive".
Dyfed-Powys Police said it was an offence to assist another person's suicide and that a "thorough criminal investigation" was required to establish the facts. 
It said the case was closed and no-one will face charges.
British law currently states anyone who is said to have encouraged or assisted the suicide or attempted suicide of another person can be jailed for up to 14 years.