MADRID, Spain (AP) _ Police in southeastern Spain arrested a 16-year-old martial arts fan Monday for killing his parents and little sister with a samurai sword.

Police arrested the teen in a train station in Alicante as he and a friend were preparing to travel to Barcelona, said Jose Luis Rico, spokesman for the Alicante police.

The search began after police on Saturday, acting on a tip from a friend of the suspect, found the slashed nude bodies of the teen's parents in their apartment in Murcia, which is near Alicante. The nine-year-old sister, who suffered from Down Syndrome, was dead in the bathtub.

Police found a bloodied samurai sword, along with several books on martial arts and Satanism, in another room.

Police, who started questioning immediately, didn't offer any possible motive for the crime.

Results of an autopsy, released to state news agency Efe Monday, showed the mother was attacked by surprise and killed by several savage sword chops to the body. The father tried vainly to defend himself.