SINGAPORE - You could say Tan Jun Wei, 19, did not know how to mind his own business.
For reasons not stated, he sent a girl SMSes telling her to break up with her boyfriend.
When the boyfriend, Mr Sam Goh, found out, he asked his friends to help deal with the situation.
One of the people he called on April 21 last year was Mr Lee Hong Jie, 21.
A meeting between the group of men turned nasty, and Tan ended up stabbing three of Mr Goh's friends with a knife. All three ended up in hospital.
The trouble began when Mr Goh told his friend Mr Lee about the SMSes that Tan, then a full-time national serviceman, had sent to his girlfriend.
In the messages he sent to the girl, Tan accused Mr Goh of not being a responsible person.
Mr Goh then asked Mr Lee to arrange a meeting with Tan to resolve the misunderstanding.
At about 6pm that day, the two friends confronted Tan at a coffee shop in Tampines about the messages.
Tan was also with two friends.
It is not clear how the men knew each other, or if they were strangers.
The two groups then went to the back of the block to smoke.
A dispute soon broke out, with Mr Goh shoving Tan's shoulder.
Mr Lee immediately intervened and told both men to resolve the matter without fighting.
The men then moved to the void deck of another block, away from the many eyes at the coffee shop.
Mr Goh called three more friends, who had earlier arranged to meet him at the gym, and asked them to join him at the void deck instead.
The three friends, aged between 17 and 18, were not told of the dispute at that point.
After they arrived, Mr Goh spoke to Tan with the rest of the men standing close by.
While that happened, Mr Lee noticed that Tan kept his hands in his pocket the whole time.
Sensing that something was amiss, he quickly asked his friends to leave the scene.
But it was too late. Tan brandished a knife and slashed the neck of his friend, Mr Dion Ku.
Feeling dizzy, Mr Ku squatted down and pressed his palm against the wound.
When Mr Goh and his two friends moved forward to protect him, Tan stabbed the two friends in the chest. But Mr Goh was spared.
So he and Mr Lee took their injured friends to Changi General Hospital.