Mr Rees was Mr Cutkelvin's partner for 28 years
A man whose terminally ill partner committed suicide in Switzerland has been arrested on suspicion of helping him end his life.
Alan Rees, 57, from Dalston in Hackney, east London, said he went with partner Raymond Cutkelvin to the Zurich base of euthanasia organisation Dignitas.
Mr Cutkelvin, 58, who had inoperable pancreatic cancer, died there in February 2007.
Mr Rees was questioned at Shoreditch police station, the Met Police said.
He was later released on bail.
Last month Mr Rees said that Mr Cutkelvin, his partner for 28 years, took a lethal dose of barbiturates.
Mr Rees said: "I wanted to be with him because this was what he wanted, to die in a dignified and peaceful manner, which is what happened.''
Assisted suicide is illegal in the UK, with a potential penalty of up to 14 years in prison.
So far no-one in the UK has been prosecuted for helping a family member die after visiting Dignitas.
A police spokesman said: "A 57-year-old man from Hackney, east London, was arrested on 17 July on suspicion of aiding a suicide.
"He was released on bail until late September, pending further inquiries."