The mother of Maxine Carr has been jailed for six months for intimidating a witness in the Soham murder trial.
Capp has been diagnosed with severe depression
Shirley Capp, 61, from Grimsby, had been found guilty at a hearing last month of threatening her neighbour, Marion Westerman.
At Sheffield Crown Court on Thursday, Judge John Reddihough said he had no choice but to jail Capp.
He said that anything other than a custodial sentence would "send out completely the wrong message".
Capp threatened Ms Westerman during an argument about a cat.
Ms Westerman had earlier told police she had seen Maxine Carr and Ian Huntley looking in the boot of a car outside Capp's house, shortly after 10-year-old Holly Wells and Jessica Chapman went missing.
She also said that Carr had been crying.
After Capp threatened her, Ms Westerman said she would not give evidence in the Soham case, however she did eventually testify.
Sentencing Capp, Judge Reddihough said: "This is a serious offence and, in recent years, courts have been very concerned at the increased number of witnesses that are threatened or intimidated."
The judge said he had taken into account the chronic post-traumatic stress disorder and severe depression Capp had been diagnosed as suffering as a result of the Soham murders.
He said he recognised the "difficulties you have faced and continue to face by reason of the notoriety of your daughter, Maxine Carr".