Josephine Backshall had placed an advert for part-time work
A 68-year-old man from Essex has been questioned over the murder of Josephine Backshall, whose body was found in Hertfordshire 36 years ago.
Police arrested the man, from the Maldon area, and later released him on bail pending further inquiries.
Mrs Backshall's body was found in a field at Bury Green near Bishop's Stortford on 1 November 1974.
She was 39 when she died and lived in Maldon with her husband and three children aged 12, 10 and seven.
The man has been bailed until April.
Hertfordshire and Bedfordshire Police cold case review unit reopened the investigation last year on the 35th anniversary of Mrs Backshall's death.
Investigator Richard Moulder said they had a good response from the public following new appeals.
Mrs Backshall's children, Christopher, Sarah and Emma, also appealed for information about their mother's death.
She was last seen by her family at about 1800 GMT on Tuesday 29 October 1974, when she left her home for an appointment in Witham, Essex.
He body was discovered on the morning of 1 November almost 35 miles away from her home. Her wristwatch had stopped at 08.10 GMT.
Mrs Backshall had placed an advert in her local newspapers for part-time work in Maldon and on 29 October, had a phonecall from someone she may have referred to as "Peter".
She arranged to meet him at 1830 GMT that night and at about 1915 GMT, a red Ford Cortina Mk 3, believed to be hers, was seen in Collingwood Road, Witham, with the bonnet up.
Police believe it is also possible that she was in the company of a man at the Fountain pub in Good Easter at 2230 GMT.