The case began with a daughter-in-law and a lawyer. In the summer of 1983 a young woman in Kempen, on the Lower Rhine, went to an attorney and told him that her mother-in-law had poisoned both of her own husbands. The prosecutor agreed to an exhumation only reluctantly. In the stomach of the dead man the toxicologist found traces of thiophosphoric acid, the active agent in E 605, the parathion pesticide then sold in every German drugstore. On July 25, 1983, the police arrested Maria Velten, sixty-seven, a grandmother known around Kempen as a warm and devoted mother of six.
After a long interrogation she confessed to killing two husbands and a partner with poison. Nine days later she volunteered more. In the early 1960s, she said, she had killed her father with a poisoned bilberry pudding when the domineering old man became an invalid who needed nursing and threatened her family life. An unmarried aunt who had taken her into the family went the same way, years later, when she too became bedridden and needed care. Velten described those first two deaths as killings of convenience. The later three were about money.
She was born in Kempen in 1916 and lost her first husband in the Second World War; two of her six children were born after it. The deep color of the bilberry pudding hid the blue warning dye in the pesticide, which is how the German tabloids came to call her Blaubeermariechen, Bilberry Mariechen, and the poison witch of the Lower Rhine. Three of the five victims ate the pudding. The other two were given poisoned medicine.
Her second husband in Kempen wanted a divorce because of the family's constant money troubles, troubles his wife had caused, in part by buying expensive presents for her children. She gave him the poison in small doses so that no one would grow suspicious, and he was treated more than once at the Kempen hospital without any of the doctors suspecting what was wrong. The fatal dose came in the bilberry pudding. Most of what she gained from the deaths, investigators found, she did not spend on herself but passed on to her children and grandchildren.
The accounts do not agree on the span. Older English-language summaries date the husbands' deaths to 1976 and 1978 and the partner's to 1980; German reporting and the 2009 television documentary put the series between 1963 and 1982. Exhumations produced conclusive findings in three of the cases, and the remains in the others were too old for the tests to settle anything, which is why she was convicted of three murders rather than five.
She was tried before the regional court at Krefeld. The filmmakers who later documented the case, and the local press, place the trial in the summer of 1983; other accounts date it to 1984, with a confession in court in September of that year. The sentence is reported as three life terms plus fifteen years, and in one German account as three life terms and two fifteen-year terms. She was eventually released from prison on health grounds and died in a nursing home on June 9, 2008, aged ninety-one or ninety-two.
On January 26, 2009, the ARD network broadcast a documentary on the case by Ute Bönnen and Gerald Endres in its series on women who kill, filmed partly in the old town of Kempen. The filmmakers presented it as a classic poisoning series by a woman who first killed to escape a situation she found unbearable and then, having gone undetected, found the same method too easy to give up. The Kempen secondary school later staged a play about her under the title Blaubeermariechen.