Seoul police on Thursday captured a 43-year-old man suspected of killing the mother of a senior member of a conservative civic group on Thursday.

The murder case has drawn keen public interest as speculation has circulated that pro-North Korea terrorists might have killed her, as her son’s group has actively engaged in a series of activities against the communist country in recent years.

The suspect, identified only by the surname Gu, has confessed to the killing, officials said. He is charged with killing her by hitting her on the head with a hammer several times and stealing 250,000 won ($222) from her on March 10.

The police also suspect that Gu with five previous convictions was involved in another robbery case that took place in Ansan, Gyeonggi Province, last April. Gu is unemployed and has never engaged in any political activities, police explained.

While searching the areas near the scene of the murder in Mia-dong, northern Seoul, police found a hammer with a blood stain at a “gosiwon,” or small one-room student accommodation located some 150 meters away from the scene. They then tracked him down at an Internet cafe.

The 75-year-old victim, only identified by her surname Han, is the mother of the secretary-general of the Korea Parent Federation, which was established in May 2006 to “stamp out leftist pro-North Korea forces.”

The killing occurred only two days before the KPF had planned to fly propaganda leaflets to the North, sparking speculation over who killed her.

Police appear to believe that the killing is simply a robbery case rather than one involving pro-North Korea activists or terrorists connected with the communist state.

Earlier, investigators looked into the possibility that an ethnic Korean of Chinese nationality might have killed her, using some circumstantial evidence along with DNA samples detected on the scene.

The KPF, with some 1,500 registered members over age 70, has sent anti-North propaganda leaflets across the inter-Korean border toward the North in recent years. It has also been leading moves to address issues over South Korean soldiers and citizens being held by the North.

By Song Sang-ho (sshluck@heraldcorp.com)