PARIS >> The French interior minister has said he fears a serial killer is on the loose after a series of murders in an outer suburb of Paris.

Claude Gueant, speaking on French radio Europe 1 today, said “maximum resources” would be used to find the perpetrator.

Investigators are looking into four murders that have taken place in the Essonne region of the capital since November.

Authorities say the same firearm was used in three of the murders, according to a police source, who spoke on condition of anonymity, citing policy.

In the latest murder Thursday, a killer fled on a motorbike after shooting a 47-year-old woman in the head.

French authorities are on heightened alert after a string of murders in southern France last month by a gunman on a motorbike.