A "predatory" man has pleaded guilty to murdering primary school teacher Sabina Nessa.
Koci Selamaj drove to London from his home in Eastbourne on the south coast to carry out a pre-meditated attack on a woman with "extreme violence".
The garage worker lurked around Cator Park in Kidbrooke, south-east, London, before targeting 28-year-old Ms Nessa as she passed through on her way to meet a friend on September 17 last year.
CCTV footage captured the moment 36-year-old Selamaj swiftly overwhelmed Ms Nessa by repeatedly striking her with a 2ft long weapon believed to be a traffic triangle, before carrying her away unconscious.
It is alleged that Selamaj then strangled her in undergrowth in what was suspected to be a sexually-motivated attack.
The body of Ms Nessa, who taught a year one class at Rushey Green Primary School in Catford, was found nearly 24 hours later covered with grass near a community centre in the park.
Selamaj, from Eastbourne, East Sussex, was arrested in the seaside town and charged over her death days later.
At an Old Bailey hearing on Friday, Selamaj, an Albanian national, paused before entering his guilty plea to murder in a whisper.
Prosecutor Alison Morgan QC suggested 30 years would be an appropriate starting point when considering the length of his life sentence because the murder was sexually motivated or sadistic.
She said: "The circumstances in which Ms Nessa's body was found demonstrated the sexual motivation that must have existed - the positioning of her legs, the exposure of parts of her body and the removal of her underwear and tights."
She said the murder was further aggravated because it involved the targeting of a lone female at night at a time of heightened concern for the safety of young women following the murder of Sarah Everard six months before.
Outlining the background to the "premeditated" murder, Ms Morgan said Selamaj had been violent towards his ex-partner, having put his hands around her neck in a strangling motion a number of times.
Three days before the attack on Ms Nessa, the defendant booked a room at the five-star Grand Hotel in Eastbourne, the town where he already had accommodation.
On September 17, he booked into the hotel and, two hours before the murder, contacted his former partner in a failed bid to engage her in sexual activity.
The defendant's Nissan Micra was tracked by ANPR cameras and cell site evidence travelling to London.
He used his bank card at Sainsbury's to buy a rolling pin, although it was never deployed as a weapon.
He entered Cator Park in Kidbrooke shortly after 8pm and lay in wait for half an hour before Ms Nessa arrived on route to The Depot bar where she was due to meet a friend.
Ms Morgan said: "The defendant is seen in effect loitering in locations around the park before spotting the deceased, checking to see if anyone else was nearby before turning and running after her.
"He is then seen to move towards the deceased and striking her repeatedly using a weapon which was approximately 2ft in length.
"The CCTV footage shows the defendant then carrying the deceased, who appeared to be unconscious by that point, up a bank and effectively out of sight."
Ms Morgan said Selamaj incapacitated Ms Nessa with 34 blows to the head from a metal emergency triangle.
Selamaj's actions afterwards were out of camera shot, but Ms Nessa was not seen alive again.
The prosecutor said: "The male did appear after 10 minutes.
"He is seen to pick up pieces of the weapon that had broken on the ground and then moved back to the area the deceased was located for another 10 minutes."
The court heard her had removed Ms Nessa's underwear and tights and pulled up her clothes so her upper body was exposed.
He then tried to cover her body in grass which was "sufficiently successful" that she was not found until about 5pm the next day.
Selamaj was also seen using wet wipes to clean a nearby bench.
On route back to the south coast, Selamaj stopped in the area of Tunbridge Wells in Kent where he disposed of the emergency triangle in the River Teise.
The defendant arrived back at the £170-a-night Grand Hotel just after midnight.
Police, who trawled through hundreds of hours of CCTV, arrested Selamaj at his home in Eastbourne on September 26.
Mr Justice Sweeney adjourned sentencing until April 7.
Speaking outside court, Ms Nessa's sister Jebina Islam broke down in tears as she said: "We as a family are broken and there is not a day that goes by that we do not think of her.
"The fact we will never know the motive for why he killed our sister is not only frustrating but heart-breaking."
Detective Chief Inspector Neil John said: "Those who knew Sabina are not the only ones affected by her murder. The events of that night shook and angered us all and the impact was felt not just across the capital but throughout the country."
Home Secretary Priti Patel said it had been a horrific and tragic case and her thoughts and prayers were with Ms Nessa's family and friends.
She said: "While such depraved acts are thankfully rare, I know that women and girls across the UK will be thinking of their own experiences.
"Let me assure them that as Home Secretary I will do everything in my power to protect them from violence and to make our country safer for everyone."
