A man has admitted sending a series of offensive and menacing messages to the social worker who first revealed the child sex abuse scandal in Rotherham.
Faisal Khan, 23, sent Jayne Senior messages filled with racist and abusive terms, including one in which he told her to "jump off a bridge".
Sheffield Magistrates' Court heard he sent 28 messages between 3 and 25 June last year.
Khan, of Main Street, Bramley, in Rotherham, will be sentenced later.
Mrs Senior helped reveal the systematic grooming and sexual exploitation of more than 1,400 children in Rotherham between 1997 and 2013.
In 2016 she was made an MBE for her services to child protection.
Prosecutor Victoria Baker said Khan had used terms including "thick scum" and "horrible racist scum" in the messages sent via Facebook messenger.
In a statement read out in court, Mrs Senior said she had been left feeling "nervous and wary" of Khan, describing him as a "sinister and dangerous man".
Upkar Bahia, defending, said his client accepted the language used in the messages was grossly offensive and malicious.
Releasing Khan on bail, magistrate Muhammad Jamil said: "This is a very serious offence and we require a pre-sentence report about your circumstances."
Khan pleaded guilty to charges of sending offensive messages and harassment without violence.
He will be sentenced on 26 January.