TOKYO - Security cameras set up at various places in Tokyo helped police identify a suspect in a recent murder case, even though the man changed his clothing repeatedly to disguise his appearance.

The suspect, Genki Matsuo, 22, was arrested Saturday on suspicion that he withdrew cash from the bank account of Kumi Arai, a 34-year-old homemaker in Itabashi Ward, Tokyo, who was stabbed to death on Nov 21.

The security cameras recorded images of the man wearing different types of clothing, from suits to a knit cap, mask and sweater.

Investigators of the Metropolitan Police Department identified the suspect despite the disguises by collecting images from the security cameras at train stations, convenience stores and other places.

Soon after the murder, the MPD compared images recorded by a camera built in the intercom system in the apartment building where Arai lived with photographs of crime suspects that the police kept on file.

The investigators found the image of the man was similar in appearance to Matsuo, who was investigated in January by Itabashi Police Station in the theft of lost or mislaid property.

On Nov 22, the day after the murder, the police learned that money had been withdrawn from Arai's account at an automated teller machine at a convenience store near Ikebukuro Station.

The man who withdrew the cash wore a knit cap, mask and scarf, apparently to conceal his face.

As many people use the ATM, it was virtually impossible to dust the machine for the thief's fingerprints.

The police were also unable to obtain important information from witnesses near the convenience store.

The police pay particular attention to the cast of a person's eyes when searching for a suspect in a crowd.

The characteristics of the eyes of a man withdrawing cash at the ATM and those of the man in the intercom camera images appeared similar.

In addition, similar glasses with black frames were worn by both men.

This deepened the suspicion of MPD investigators that Matsuo was the man they sought.

The investigation headquarters set up at Takashimadaira Police Station collected photo images from security cameras near the convenience store and analysed them.

More than 20 officers, about half of the investigators in the case, were given the task of analysing data from security cameras.

The investigators looked through a huge number of photos searching for a person matching the suspect's appearance by checking faces, clothing, height, physical features and gait.

They learned that a man had bought a knit cap, sweater and scarf--similar to those used by the suspect at the ATM--at a clothing store near the convenience store, about 30 minutes before the victim's money was withdrawn.

In addition, the investigators learned from the photos that a man in a suit had changed his clothing in a pachinko parlour's toilet.

The deciding factor was security camera images of a man who removed his mask near the convenience store to clearly show his face.

As a result of graphic image analysis, the police identified the man as Matsuo and it was used as grounds for requesting an arrest warrant.

"In urban areas, it's difficult to obtain good information by interviewing residents, so security cameras are a very useful tool," a senior MPD official said. "They will continue to be used to provide objective evidence."

According to Matsuo's acquaintances and investigators, the suspect is from Fukuoka Prefecture. He quit a junior college in that prefecture in 2008 when he was a first-year student and came to Tokyo.

He worked in a mah-jongg parlour in the Kabukicho district in Shinjuku Ward for about two years.

After a while, he moved out of his apartment, telling acquaintances he planned to leave Tokyo.

He returned to Tokyo in December last year and began working as a part-time worker at a karaoke parlour near Ikebukuro Station.

He was transferred to a karaoke parlour near Narimasu Station on the Tobu Tojo Line in March.

He moved to his current apartment and continued to work.

But around September, he quit his job, telling others, "I'm being hired by an information technology company as a regular employee."

According to his acquaintances, on Nov 20, the day before the murder, Matsuo gleefully told them he visited Tokyo Disneyland with his girlfriend.

One acquaintance said, "I once heard him say he had done some shoplifting, but I didn't think he was a man who could commit such a serious crime."