The family of an Adelaide teenager brutally murdered in a classroom in 1978 has been dealt a devastating blow, with the prime suspect in the case dying without facing justice.

Lina Marciano’s sister, Teresa Kellett, vividly recalls the fateful day when she last saw her alive. On March 1, 1978, Lina left their Wayville home on her blue and white Honda motorcycle, heading to Nailsworth Primary School for dancing lessons. 

Teresa’s instincts told her something was amiss and after an agonising three-day search, Lina’s body was discovered in a rubbish tip at Dry Creek. 

The post-mortem examination revealed evidence of binding, gagging, strangulation, stabbing, and blunt force trauma to the head.

Detective Allen Arthur, who worked on the case in 1992, described the murder as one of the most horrific he had encountered, an “overkill situation”.

Teresa echoed this sentiment, describing the crime as “brutal” and “horrible”.

Investigators believe Lina was abducted from the school grounds and murdered in one of the classrooms.

A breakthrough in the case emerged when a cleaner at the primary school contacted the police, identifying a suspect. However, in a disturbing twist, the woman was then attacked by an unknown man who told her to “keep her mouth shut”.

Despite formally interviewing the suspect and collecting his DNA, police lacked sufficient evidence to charge him.

Now, with his recent death, any secrets he held have been buried with him.

“That was our last line of hope, and he’s gone,” Teresa said.