Inspector-general of police Khalid Abu Bakar said the suspect who was arrested for a shooting rampage at the Lim Chong Eu Expressway in Penang last night had a military background.

Khalid said the 35-year old bodyguard, who was detained with another suspect, was also "mentally ill".

The other suspect, a 32-year old man, was in the same car as the Datuk who was reportedly shot by the bodyguard.

Both suspects would be remanded for seven days.

On the motive, Khalid said it was best left to the courts to decide.

"From initial investigation, the suspect has a mental problem but has no prior criminal record," Khalid said during a press conference at Universiti Sains Malaysia.

According to Khalid, police also had seized a weapon from the crime scene. The weapon was owned by a security firm.

He said the suspect who opened fire had a "carry and use" licence.

Yesterday, three people, including the 32-year-old Datuk, were shot dead in the 7.30pm incident.

Four people, including a cameraman from Radio-Television Malaysia (RTM), were shot.