By Chong Shin Yen and Vivien Chan

TO SOME, he was an extrovert with many friends.

To others, he seemed more like a loner, a smart guy with a few close friends.

Even his hostel neighbour did not know much about him.

But something made him snap yesterday morning. And a young man with a bright future is now dead, and his professor is in hospital with stab wounds.

David Hartanto Widjaja, 21, a final-year Indonesian undergraduate at Nanyang Technological University (NTU), attacked his professor with a knife before fleeing and taking his own life soon after.

Associate Professor Chan Kap Luk, 45, who is from the Division of Information Engineering, is recovering from his injuries after undergoing surgery at the National University Hospital (NUH).

Both professor and student are from the School of Electrical and Electronic Engineering (EEE).

What could have made an above-average, seemingly well-adjusted student like Widjaja, who was understood to be an Asean scholar, suddenly resort to violence?

There seemed to be hardly any warning signs that he would snap. A hostel neighbour who saw Widjaja on Sunday night didn't notice anything unusual.

Widjaja's close friends, who might have been able to shed some light on his recent frame of mind, were too distraught to be interviewed last night.

Even Prof Chan had not detected any signs of stress in Widjaja, though he did notice his student's work had slipped recently.

Widjaja was having some problems with his Final Year Project, which had about a month to go for its final submission.

Whether the project had anything to do with the attack is not clear, but they were discussing it when he attacked the professor.

It would also seem that he had planned the attack as he had taken the knife with him when he went to Prof Chan's office on the sixth storey of Block S1.

At about 10.30am, while Prof Chan's back was turned, Widjaja suddenly whipped out the knife and stabbed him.

NTU President Su Guaning recounted the attack to reporters after he visited Prof Chan at NUH.

Dr Su said there was no argument between the two men before the attack.

'He told me that he had his back to his student and they were looking at his computer discussing the project when he suddenly felt a sharp pain in his back,' Dr Su said.

'Prof Chan turned around and saw his student holding a knife. There was some struggling and Prof Chan managed to grab the knife from him.'

The bleeding professor ran out of the room. Widjaja, who had slit his own wrists, ran off in the opposite direction.

Dr Su said that by then, other professors were alerted and rushed to Prof Chan's aid.

Widjaja later ended up on the glass roof of a bridge which links the EEE school to another building, Techno Plaza.

The New Paper understands that after the attack, Widjaja made his way to B2, a level below the staff offices. He climbed over the parapet onto the roof of the covered link-bridge.

He sat there cross-legged, leaving bloodstains on the bridge. Witnesses said they saw a trail of blood from the professor's office to the bridge.

Mr Tuen Choy Fa, 56, a plumber, recounted: 'I saw the boy sitting there with a lot of blood. I did not notice if he was holding anything.

'I shouted at him, 'Hey! What are you doing?', but he just stared blankly. He seemed to be in a daze.'

Traumatised

Sensing something amiss, and fearing for the student's safety, Mr Tuen ran into a nearby office to get help.

When he came out with some of the staff, Widjaja had already fallen five storeys to his death.

Mr Tuen said: 'It is such a loss, a life is lost.'

Dr Su said that just before Widjaja leapt from the bridge, a female student saw him sitting there and had tried to persuade him to come down.

Widjaja jumped before her eyes. The traumatised student is receiving counselling.

The attack shocked students who returned to campus yesterday after a one-week mid-term break.

Prof Chan, who is originally from China, underwent emergency surgery to his back and his right hand.

He suffered a deep stab wound to his back and cuts to his right palm. The vein in his index finger is severed but the injuries would not affect future movements of his hand, said Dr Su.

'It is very fortunate that he had not injured his vital organs,' said Dr Su, who spoke briefly to Prof Chan after the latter was pushed out of the operating theatre.

Prof Chan told Dr Su that Widjaja was an above-average student and had been doing well in his studies until recently.

Dr Su said: 'He told me that the student hadn't been progressing well and had some problems with his Final Year Project.

'But Prof Chan added that with some work, the student should be able to pass his final year.'

Dr Su added that Prof Chan was shocked at what happened as Widjaja had appeared normal and showed no signs of being stressed or distressed.

Instead of worrying about his own injuries, Prof Chan told Dr Su he felt sorry that he had not detected anything wrong with Widjaja.

'He had a sense of regret that he couldn't help him (Widjaja) earlier,' said Dr Su.

He said the university was 'deeply shocked and saddened' and would investigate the matter thoroughly.

Some of Prof Chan's colleagues and his students also visited him at NUH yesterday.

Prof Chan's wife, who is also from China, was calm and kept vigil by his bedside. She declined to comment.

Prof Chan, a father of two young children, has been teaching in NTU since 1992.

He was also Widjaja's supervisor for his Industrial Attachment when he was in Year 3.

Extrovert, lots of friends

Mr Radyum Ikono, former president of the Indonesian society in NTU, said Widjaja was a member of the club but he did not know him well.

But Mr Ikono added: 'He was an extrovert with a lot of friends.'

An Indonesian student, 22, who attended the same high school as Widjaja in Indonesia, described him as sociable.

'He was one of the top students who was famous. People in school know him because he was smart,' said the woman, who declined be named.

Smart he was indeed. He was part of a team that participated in the International Math Olympiad in 2005.

Widjaja was also part of a team that emerged first runner-up at the NTU Cyberathletics Open 2009 in January.

The president of NTU's Cybergames Society, Mr Ho Pin Yan, 24, said of Widjaja: 'He was very good in gaming, and was a smart gamer too. He was one of the top few gamers in NTU.'

But not everyone thought that he was an extrovert.

An Indonesian student who met Widjaja in Singapore said he kept mostly to himself.

A member of the Indonesian society, the male student, who requested anonymity, said: 'He didn't take part in our activities and he didn't talk to us.'

Widjaja was a resident at NTU's Hall of Residence 4, staying in a single room on the first floor. Despite having stayed there for at least a year, his floor mates did not know him well.

His neighbour, who wanted to be known only as Jimmy, 24, said that Widjaja was a 'normal guy'.

'Like a typical guy, his room is a little bit messy,' said Jimmy, who also said that Widjaja liked to play computer games.

'Sometimes, when I'm about to sleep, around 3am, I can still hear him playing games.'

Jimmy last saw Widjaja the night before.

Recalling their last meeting, he said: 'Shortly after midnight, I went to the common toilet on our floor. I saw him brushing his teeth.

'We greeted one another. He seemed normal, nothing unusual.'

Mr Indra Yudhistria, 22, a final-year undergraduate who lives in the same hall, said that although they were both Indonesians living in the same hostel, they did not know each other well.

A colleague of Prof Chan said the professor is generally a nice person.

She added: 'We (the staff) were very shocked that such a thing happened to him.

'I think it's probably a problem with the student, and not a problem with the lecturer.'

Other professors declined to comment on the incident.

A police spokesman said they received a call around 10.30am informing them of a body lying motionless at the carpark of Block S1 in NTU.

It is understood that Prof Chan was semi-conscious when he was taken to NUH, with multiple stab wounds to his back and arm.

Additional reporting by Pearly Tan and Geraldine Yeo

This article was first published in The New Paper.