Stuttgart, Germany - The father of a youth who shot dead 15 people and himself at a German school this year is likely to be indicted for leaving the murder weapon unsecured in his home, officials said Thursday.

Local prosecutors had intended to impose a summary fine only on the father of Tim K, aged 17, for homicide by negligence.

But the Justice Ministry of Baden-Wuerttemberg state said the state prosecutor would instruct the local prosecutor to take the case to trial.

Police said the gun had been kept in the bedroom of K's parents. The youth's attack on the school at Winnenden in March appalled the world.

Prosecutors will argue that failing to lock up the gun was a breach of legal duty and an act of negligence that led to the homicides. (dpa)