Teacher Sabina Nessa is thought to have been murdered during a five-minute walk to meet a friend in a pub, police have said.
The 28-year-old never arrived and is believed to have been attacked in Cator Park in southeast London.
Ms Nessa, who taught at Rushey Green Primary School, left her home in Astell Road, between Eltham and Lewisham, just before 8.30pm last Friday, detectives said.
Her body was found close to the OneSpace community centre, inside the park, at about 7.30pm the following day.
Her destination was The Depot, a pub on Pegler Square in Kidbrooke Village.
“Sabina’s journey should have taken just over five minutes but she never made it to her destination,” Detective Inspector Joe Garrity said.
“We know the community are rightly shocked by this murder – as are we – and we are using every resource available to us to find the individual responsible.”
A post-mortem examination, carried out on Monday, was inconclusive.
Mr Garrity added that “good progress” is being made in the investigation and specialist officers remain at the scene, conducting “intensive searches” and enquiries.
He continued: “We are incredibly grateful for all of those who have so far come forward and spoken to us but we believe there are still others out there who may have information that could help.
“If you think you saw Sabina or any suspicious behaviour in or around the park on Friday evening please speak to us.”
A man in his 40s was arrested on suspicion of murder and released under investigation, police said previously.
The headteacher at Ms Nessa’s school, Lisa Williams, said her death is “desperately sad”, adding that she was “kind, caring and absolutely dedicated to her pupils”.
Anyone with information should call the incident room on 0208 721 4266, or Crimestoppers, anonymously, on 0800 555 111