A man arrested following the discovery of nine dismembered bodies at his apartment used a Twitter account with the username "hangingpro," boasting knowledge about hanging, to get in touch with people who wanted to commit suicide, investigative sources said Thursday.

Takahiro Shiraishi is believed to have opened the account in September with a profile saying he wanted "to spread my knowledge of hanging and be a help to those who are really in pain."

Using the "hangingpro" handle, Shiraishi replied to women who had expressed suicidal feelings on Twitter with messages such as "Let's die together," the sources said.

Man says teens among 9 victims he killed and dismembered: sources

9 dismembered bodies found in man's apartment near Tokyo

On Oct. 6, "hangingpro" wrote, "It is not good to tell friends, family members and social networking sites that you are going to die before committing suicide."

The post is being seen as an attempt to prevent people contemplating suicide from being dissuaded by those around them, the sources said.

Police believe that the 27-year-old unemployed man invited people who wished to die to his home in Zama, Kanagawa Prefecture near Tokyo by contacting them through Twitter, and then killed them.

Investigators have found that Shiraishi used multiple Twitter accounts to contact the victims.

The sources also said personal belongings of the victims, such as clothes and mobile phones, have not been found at the suspect's home, posing a challenge for identification of the victims.

Regarding the bodies, police quoted Shiraishi as telling them that he "threw away parts (of them) after dismembering them in the bathroom." A resident near Shiraishi's apartment said she frequently witnessed the suspect disposing of plastic bags at a garbage collection point in the neighborhood.

The nine victims are believed to be a man around 20 years of age and eight women.

Shiraishi has told the police that out of the nine he killed, four were around 17 years old, four were aged around 20, and one was in the late 20s.

He said he does not know the exact names and ages of the victims, according to police.

In trying to identify the victims, police are believed to be working on matching their DNA with a database of the DNA of missing people that has been collected since April 2015 at the families' request.

As of end of September, the database has registered the DNA of some 4,000 people who are feared to have committed suicide or gone missing due to involvement in a crime or accident.

The killings came to light on Tuesday following a police search into the disappearance of a 23-year-old woman from Hachioji in the western suburbs of Tokyo in late October, whom Shiraishi has also admitted having murdered.

Shiraishi was arrested Tuesday on suspicion of mutilating a body of unknown identity, hiding it inside a cooling box and disposing of it between August and October.

The nine bodies were discovered in seven of eight cooling boxes found in his apartment. Knives with blood stains, ropes and strapping believed to have been used in the killings were also found there.