A MAN has killed three of his neighbours and seriously injured at least two others after he went on a stabbing rampage at his apartment building in Valencia.

An interior ministry official said the suspect left his upper-floor apartment late on Friday and went downstairs knocking on doors at random as he descended. As residents answered the door he reportedly launched an attack on them.

A 50-year-old man and his 13-year-old son were among those killed, while the boy’s mother, 48, suffered serious injuries after being knifed in the chest and abdomen.

A 77-year-old woman was also stabbed to death when she answered her door.

Another resident, a 44-year-old man, is recovering in hospital with stab wounds to his back and head.

Police have arrested a 33-year-old man, who was reportedly caught nearby covered in blood. No motive has yet been determined.