Police in the North are seeking a man with a record of violence against women who is believed to have been in contact with the pregnant mother of four murdered in Derry last weekend.
They PSNI says it believes 30-year-old Stephen Cahoon may have crossed the border into the Republic.
He is believed to have been in touch with 30-year-old Jean Quigley in the weeks before she was beaten to death at her home in Derry last week.
Cahoon served a jail term in the North after convictions in 1999 for violent assaults on two women with whom he had relationships.
The PSNI have been liaising with Gardaí in connection with the case.
Mrs Quigley's funeral is due to take place tomorrow.