Sebilla Alida Johanna Niemans (27 September 1927 – 31 October 1959), known as Blonde Dolly, was a Dutch prostitute and businesswoman who was murdered by strangulation.

When she was young, after her chronically ill mother was admitted to hospital, Niemans and her elder brother were sent to the Groot Kijkduin children's home in Zandvoort.

When Nazi Germany occupied the area during the Second World War, Niemans and her brother went back to Amsterdam to live with their father, who by now had become married to a new wife.

However, Niemans's marriage to van den Bergh broke down after a year and, following a lengthy and complex legal procedure, the couple were divorced in 1957.

There was speculation that Niemans's "blue book", which the police refused to release to the public, contained names of high-ranking regular customers.

[1] The main suspect in the case was a bodyguard named "Gerard V", whose services Niemans had used after another prostitute, Marietje van Es, had been robbed in December 1958.