Tracey, just 13, was also allowed to visit her friend Lynette who lived nearby.
The sisters left their home together until parting ways at Great North Rd.
Tracey turned left, Debbie turned right.
"She said 'see you later then' and I said 'yeah, see you later'," said Debbie from her home in England.
"I didn't look back, I thought I would be seeing her again in a few hours' time."
Tracey never came home. Her murder remains unsolved.
"It still haunts me that I didn't look back to see her that one last time and to this day, when I say goodbye to someone I love, I have to look them in the eye when I say it," says Debbie on the 37th anniversary of the murder.
She's hopeful that further publicity on the cold-case will trigger someone's memory, or guilty conscience.
Tracey Patient was last seen at 9.30pm on January 29, 1976, on Great North Rd outside the old Henderson police station. She said goodbye to her girlfriend before crossing the road to ask an elderly couple the time.
Appearing upset that she was late, Tracey ran towards her home 1.6km away. She never made it. A man walking his dog found her body in the Waitakere Ranges, strangled with a pantyhose tourniquet.
Debbie Sheppard remembers her father coming home from the police station the next morning with their neighbour, who was a police officer in Henderson.
Her youngest sister Denise, who was 8 at the time, asked when Tracey was coming home.
"My dad said 'She's not coming home'. Denise asked why and he said 'Because she's dead'. It sounds harsh, but he was still in shock," says Debbie.
"Denise was sitting on my lap and we just held on to each other as if we would never let each other go. Mum and Dad sat on the other sofa, clinging to each other."
The following days and weeks are hazy for Debbie, but some things have stuck in her memory.
"I remember being at a friend's house and the silence that came upon everyone when the news came on and they were reporting on Tracey's murder.
"I remember people crossing the road to avoid having to talk to me. It hurt at the time but as I got older I realised they were not being unkind, they just didn't know what to say to me."
The Patient family moved back to the United Kingdom, a time which was so hard that Debbie "can't begin to describe what it was like".
Then, two years after the murder, they received a 4am phone call.
The police found Tracey's signet ring in a wastepaper basket at an Avondale shopping mall after an anonymous phone tip. The informant quoted the number 126040, but police were unable to trace the caller, or decipher the code.
"We couldn't believe it," said Debbie. "We hoped that this would be the clue that the police needed to find Tracey's murderer."
But nothing came of it. Eventually, Debbie gave up hope of the killer being caught. Worse, she blamed herself.
"I believed that I was responsible for Tracey's death. I knew that if I hadn't asked my parents if I could go out, Tracey would have stayed safe at home that night."
Grief would overwhelm her if she read a story about a child being killed, or watch a sad film, even see a friend arguing with a brother or sister.
It was especially hard when younger sister Denise turned 13, who was blonde like Tracey and looked similar at that age.
"I got blind drunk on the day of Denise's birthday and spent the whole of her 13th year absolutely terrified that she would die."
While her parents became the founding members of a support group, Parents of Murdered Children, and would often leave the house in the middle of the night to comfort others, Debbie blamed herself for 15 years.
Her body and mind began to shut down, racked by chronic fatigue syndrome and depression. She finally visited a bereavement psychiatrist.
"He made me realise that I was not weird for having to look people in the eye when I said goodbye to them, or checking my wardrobes and cupboards before I went to bed at night in case someone was hiding in there.
"Or bursting into tears when I heard a sad story on the news, or not being able to bear wearing anything that fitted tightly around my neck."
Debbie also met her future husband, Gary, who encouraged her to talk about Tracey - something she had never really done.
As the years since the murder mounted up, she was resigned to the fact that her sister's killer would never be found.
But in June 2004, her parents received a letter from friends in New Zealand. A story about the cold case aired on the Holmes television show had triggered new interest. The police received more than 100 calls in three days.
Since then, Debbie has followed media interest including a story from a West Auckland community paper which stated that "small items of evidence" had been sent away for forensic testing.
The police have never told Debbie the results and also declined to comment to the Herald.
This was followed by the Sensing Murder programme, which led two psychics to nominate a suspect. Police later interviewed the man but his alibi, that he was at the Doobie Brothers' concert, could not be verified.
Other suspects have been nominated and detectives have worked on the case in recent years.
"I want to do more for Tracey than put flowers on her grave," said Debbie.
"The only thing I can do is keep her story in the public eye in the hope that someone will come forwardone day."
Can you help?
* Anyone with information about Tracey Ann Patient's death is urged to call Waitakere CIB on (09) 839-0600.
* Alternatively, people can call Crime Stoppers anonymously on 0800-555-111.
Famous cold cases
The Crewe murders
New Zealand's most infamous cold case, the killing of Harvey and Jeanette Crewe in June 1970. They were shot and killed on their farm at Pukekawa. Their bodies were dumped in the Waikato River.
The deaths led to books, documentaries, conspiracy theories and local farmer Arthur Allan Thomas being convicted twice of murder.
It was after he was pardoned in 1979 that suspicion fell on Mrs Crewe's father, Len Demler, considered by some to be the prime suspect. The Crewes' 18-month-old daughter Rochelle was alive in the house and it was suspected that an unknown woman had fed her for up to five days.
After Mr Thomas was jailed, it was discovered a cartridge case with marks - showing it had been fired from his rifle and proving critical for the prosecution - had been planted in the garden by police.
Kirsty Bentley
Kirsty Bentley vanished on New Year's Eve 1998 while walking her dog beside the Ashburton River near her home. Searchers found the 15-year-old's battered body two weeks later in the Rakaia Gorge.
After an initial search her dog was found tied to a tree near the Ashburton River and underpants were discovered nearby. Police never established a murder scene and have explored theories that the killer may have staged that scene to throw them off the trail.
Eleven years after the murder, the latest officer to lead the inquiry, Detective Inspector Greg Williams, revealed he had never been convinced Kirsty was attacked and killed at the riverbank.
At various times throughout the investigation both Kirsty's brother, John, and father, Sid, were suspects but they have both strongly denied any involvement.
Kayo Matsuzawa
Japanese tourist Kayo Matsuzawa, 29, was murdered just hours after she arrived in Auckland in September 1998. She checked into the Queen Street Backpackers, telling them she wanted to stay three nights. Then she walked up two flights of stairs to room 25, put her bags on her bed and headed outside again.
Ten days later her body was found in a locked fire-alarm cupboard of a stairwell linking the Centrecourt and BNZ buildings in Queen St. She was naked and her body decomposing. On the 14th anniversary of the murder police said that while they had no new leads, they remained hopeful of solving the case.
Angela Blackmoore
Angela Marie Blackmoore was 10 weeks pregnant when she was murdered in the kitchen of her Christchurch home in August 1995. The 21-year-old had been stabbed more than 39 times while her 2-year-old son, Dillon, slept nearby. Ms Blackmoore's partner Laurie Anderson found her body when he returned from work about 11.20pm.
There was no forced entry to her house. Police believe the killer knew Ms Blackmoore as it appeared she had opened the door to him. A bloody shoeprint left at the scene, thought to be the killer's, has never been matched. Despite an extensive investigation, which at one point employed 35 detectives fulltime, neither the killer nor the murder weapon was found.
Claire Hills
Claire Hills' murder was described as one of the most callous in New Zealand history. The 30-year-old was abducted at traffic lights in Auckland in the early hours of April 28, 1998. Her abductor took her to the top of Mangere Mountain in South Auckland, parked her car behind the clubrooms in the secluded hill domain, doused her in petrol and set her alight.
A local woman exercising in the park caught a glimpse of the murderer as he lit the fire. When the killer spotted the woman he ran away.
Last year Detective Inspector David Lynch said police received fresh information on the case from time to time which was investigated by a team of detectives.
