The couple met while working at the Institute of Technical Education (ITE), and married in 1993.

However, the relationship was a rocky one, and they separated two to three years ago.

On Thursday evening, things came to a tragic end when Mr Seet Cher Hng allegedly stabbed his wife at the ITE Central College campus.

According to a source close to Mr Seet, the couple have a son and daughter, and had been living separately the past few years.

Mr Seet, 66, was arrested yesterday while warded at Tan Tock Seng Hospital for the murder of Ms Low Hwee Geok, who was found dead in the Ang Mo Kio school's carpark.

After allegedly attacking her, Mr Seet is understood to have stabbed himself and sustained serious injuries. He is still warded but is no longer in critical condition.

The police were alerted to the incident at 7.40pm on Thursday. Ms Low was found lying motionless next to her car, and was pronounced dead by paramedics.

The police have classified the case as murder.

Ms Low, 56, who also went by her English name Michelle, was director of ITE's examinations division. She and Mr Seet had been working at separate campuses the past few years.

Last year, Mr Seet retired from his role in the estates services department at ITE College West in Choa Chu Kang.

The source also said Mr Seet had a temper and rarely talked about his family. He added: "In contrast, Michelle was soft-spoken and helpful. She had a lot of lunch buddies."

In a statement yesterday, an ITE spokesman extended its condolences to Ms Low's family, and said it would be providing support.

"She was very well regarded by her colleagues for her warm personality, as well as passion and professionalism in her work," said the spokesman.

ITE management also met Ms Low's colleagues yesterday to provide support and counselling.

Friends of Ms Low who were at the morgue yesterday morning also spoke well of her.

Reverend Ian Buntain, 61, her pastor for two years at Grace Baptist Church near MacPherson, told reporters that Ms Low was a regular at the church.

"She was a lovely, joyful soul, very gentle, always had a smile. Everyone who met her loved her, so it is quite a tragedy for everyone," said Rev Buntain.

"People should know she made a great impact on those who knew her," he added.

A church friend, who declined to be named, said Ms Low joined the church alone two years ago, and was a devout Christian.

According to a blog post by the church, Ms Low leaves behind her 18-year-old daughter, seven sisters and mother.

Another pastor at Grace Baptist Church, Mr Oliver Chia, 46, said: "She was a lovely lady, very faithful, committed and friendly when we talked to her, although she was new."

He added that Ms Low did not share much about her personal life.

"Our role now is to care for the family and take our cue from how the family wants us to support them," he said.

When The Straits Times visited the school yesterday morning, lessons were going on as usual.

However, many students and staff were overheard discussing Thursday's incident.

The campus houses amenities such as a supermarket, a bookshop and restaurants open to the public.

Some students were also spotted congregating at the scene of the incident, where Ms Low's car was still parked at around 1.30pm.

In response to questions about security on campus, the ITE spokesman said: "This is an isolated incident involving a staff (member) and her ex-husband.

"We would like to assure students, staff and members of the public that security measures are in place to safeguard the safety of our campus."

• Additional reporting by Cara Wong

Correction note: An earlier version of this article misspelt Mr Seet Cher Hng's name. We are sorry for the error.