France fears serial killer on the loose after Paris murders

French authorities fear a serial killer could be loose in Paris after four killings in suburban housing estates in five months were linked to the same gun.

All the victims were shot with the 7.65-mm pistol by a gunman who fled on a motorcycle, recalling the attacks of the Islamist extremist who killed seven people in Toulouse before he was killed himself by police last month.

The latest victim, Nadjia Boudjemia-lahcenea, 47, of Algerian descent, was shot dead in the entrance hall to her block of flats in the Grande-borne district of Grigny, south of the capital, on Thursday.

Interior minister Claude Gueant vowed to hunt down the killer.

Unlike the Mohamed Merah killings in Toulouse, there is no suggestion of any political or religious motives.

But with ballistics analysis showing that the same weapon had been used in all four attacks, police now suspect a serial killer may have been behind all four deaths in a 10-kilometre radius.

Several witnesses said they saw a tall, thin white man wearing a black motorcycle helmet in the vicinity, according to Le Parisien newspaper.

The suspect wore a dark leather bomber jacket and carried a small bag. He is believed to drive a blue Suzuki GXSR 1000 motorcycle. It is thought the bike has no licence plate.

“We are putting every effort into finding out who is behind this,” Gueant said in a radio interview. The first victim was Nathalie Davis, a 35-year-old laboratory assistant who was also shot dead in her building in Grigny on Nov 27.

Prosecutor Marie-suzanne Le Queau said all the attacks appeared to have been committed at the same time of the day, between 4 p.m. and 6 p.m., adding that about 100 investigators were working on the case and that identity checks would be stepped up.