A professor at a Beijing law school was stabbed to death by a student on Tuesday, the third such attack in China in less than a month, the Beijing News reported yesterday.

Cheng Chunming, 43, a professor at the University of Political Science and Law, was attacked by a student wielding a kitchen knife as he was preparing to take a class at the Changping district campus.

Witnesses said the student entered the classroom at about 6:40 pm and stabbed Cheng twice in the right side of his neck.

Paramedics were called, but Cheng died on the way to hospital, the report said.

Doctors at the Changping Chinese Medical Hospital said Cheng's carotid artery had been severed and that a cervical vertebra had been fractured. The cause of death was recorded as excessive blood loss.

The attacker, identified as a 22-year-old final-year student surnamed Fu, is now in police custody, university spokeswoman Liu Changmin told a press briefing yesterday.

He is being questioned about his motive for the attack, she said.

Witnesses said that Fu, after making the attack, appeared calm and used his own mobile phone to surrender to police, the newspaper said.

Soon after the attack, an anonymous message was posted on the school's intranet bulletin board claiming Cheng had been "in a relationship" with Fu's girlfriend.

However, Liu told China Daily yesterday the claim was only a rumor, and that "nobody had ever reported the relationship to the university".

"Discussing such a rumor at this time is irreverent to the victim," she said.

According to the Beijing News, Cheng's wife is currently five months pregnant.

Last night, she visited the campus with her family and friends, but collapsed in tears several times, the newspaper said.

Liu said a team has been set up at the university to provide Cheng's wife and family with any emotional support they might need.

Psychologists will also provide counseling to the students who witnessed the stabbing, she said.

"We are all very shocked by the incident, and have reminded all students to be on alert for their own safety," Liu said.

Several tributes have been posted on the university bulletin board, referring to Cheng as a "distinctive and romantic professor", the Beijing Youth Daily reported yesterday.

One student wrote: "We will never again see his trademark plaid trousers on campus."

Cheng is the third teacher to be killed by a student in less than a month.

On October 4, a 16-year-old boy stabbed to death a 23-year-old teacher in Shanxi province. The boy had earlier written in his diary that he hated society and teachers. His parents had recently divorced, reports said.

On October 21, a 16-year-old truant in Zhejiang province strangled to death a teacher who had gone to his home to find out why the boy had not turned up for class.