Prosecutors investigating the Sung Woan-jong bribery scandal have added three men to their probe list -- lawmakers Lee In-jae and Kim Han-gil and Roh Gun-pyeong, the elder brother of the late President Roh Moo-hyun.

Sung, a construction tycoon who once held a National Assembly seat, named eight politicians who allegedly received his money before he took his life in early April. None of the three was on the list, which means prosecutors found something to investigate in the process of probing people who were close to Sung and the eight, which included former Prime Minister Lee Wan-koo and President Park Geun-hye’s close associates.

Prosecutors questioned Roh Wednesday in relation to the two presidential pardons Sung was granted, in 2005 and 2007, when his brother was the president. Prosecutors said they suspect the senior Roh peddled influence at the request of his hometown acquaintance, who acted as a middleman between him and Sung.

Lee, a Supreme Council member of the ruling Saenuri Party, is suspected of receiving 20 million won ($18,000) from Sung in 2012. Lee, hailing from the same Chungcheong region as Sung, is a veteran politician who once ran for president.

One can easily imagine Sung, who ran vast human networks and made aggressive payouts to buy influence, had a close relationship with Lee. Sung’s diary showed that Lee met Sung 32 times between April 2012 and September 2014.

Kim is the first opposition politician publicly mentioned by prosecutors. Kim, too, was close to Sung, having met the tycoon 24 times during the same period, according to Sung’s schedule. Moreover, the two had dinner on the eve of the day Sung committed suicide.

So it was hardly surprising to hear prosecutors say Kim allegedly received 30 million won around the time of the May 2013 leadership race for the main opposition party, which Kim won. The allegation involving Kim reminds one of what Sung once said: He gave money to ruling and opposition politicians alike and that therefore it would turn out all right for him whatever side won power.

As things stand, Kim’s denial of the allegation is unconvincing, and the New Politics Alliance for Democracy’s accusation that the prosecution pointed to Kim out of political considerations makes little sense.

Prosecutors said they were talking with both Lee and Kim about when they would undergo questioning. Both should comply with the interrogation plans at the earliest possible date.