A school student stabbed his girlfriend to death before attempting to take his own life by jumping from a building in Bangkok. His suicide attempt failed, leaving him with serious injuries.

Police were called to the Eua Arthorn housing project on Ram Intra Road at around 9.30pm on Thursday.

They found a 20-year-old man lying in a pool of blood on the ground, crying out in pain. He was rushed to a nearby hospital.

The team found a dead woman on a walkway between the 3rd and 4th floors. She had multiple stab wounds to her chest, stomach, neck and left side of her face. A blood-stained knife was found near her, said the police.

According to police, the two individuals were lovers. The injured man was a Mathayom Suksa 6 student and lived in a room on the 4th floor. The slain woman was a frequent visitor to his building.

Before the fatal attack, a caretaker of the building noticed the student attempting to jump from the 4th floor. Despite the caretaker's efforts to dissuade him, the student cried and said, "I can’t live any longer because she’s dead". The 20-year-old suddenly jumped from the building.

Police initially suspected that the couple might have had an argument due a love triangle, leading the man to stab her in a fit of jealousy.