Police on Wednesday obtained an arrest warrant for a 32-year-old man on suspicion of fatally shooting a "shinkin" bank employee during a robbery in Tokyo's Edogawa Ward in December.

Investigators said they have placed Kazuyuki Tominaga, who has no fixed address, on a wanted list for his suspected involvement in the robbery, in which Tokyo Bay Shinkin Bank employee Keiji Toyohara, 46, was shot to death as the robbers made off with 46.6 million yen from a bank car.

According to police investigations, Toyohara was driving the vehicle, which belonged to the bank's Funabori branch, in a street in Edogawa Ward on Dec. 29 when it was ambushed by two masked men in another vehicle. One of the men shot Toyohara, who was taken to a hospital and later died.

Police sources said investigators suspect a second suspect in the assault is a Chinese acquaintance of Tominaga, in his twenties. Police are currently searching for him.

The car used in the attack was found abandoned near the scene of the crime soon afterward, and police have been interrogating two men suspected of stealing it from a car dealer in Narita, Chiba Prefecture. Police said a source close to a gangster organization said Tominaga had the group dispose of a gun. A search of a Chiba river led to the discovery of a gun, later confirmed to be the weapon used in the robbery.

Police also received an anonymous tip that Tominaga was in the car used in the ambush, and ensuing investigations have led police to determine that Tominaga was involved in the crime, investigators said.