"She [the ambassador] also expressed concern over political violence ahead of the next elections," Reza Kibria, son of slain Awami League (AL) leader Shah AMS Kibria, told a press briefing.

Referring to the US Congressmen's concern about the inadequacy of the progress made in the investigation and prosecution in the murder case of former finance minister Shah AMS Kibria, Patricia Butenis told journalists, "This is a special case that should be looked into seriously."

"I also expressed sympathy for Mrs Kibria," the ambassador said after a visit to Kibria's family at their Dhanmondi house where she talked with the family members of slain Awami League (AL) leader Shah AMS Kibria for about an hour.

"The ambassador inquired about the security of our family and appreciated our continuous effort to bring the perpetrators of our father's killing to justice," Reza Kibria said, adding that their family wanted assistance of the US government for the international probe into the Kibria killing case.

"Our father was killed, as proper investigation was not done in case of such killings before. And if we do not try to bring the culprits to justice, father of somebody else will be killed in the same way," Reza Kibria said.

No one has security while the godfathers of the political killings remain unidentified and beyond the reach of justice, Reza said, adding, "Fair election is not also possible oo if there is dominance of guns and money and if the kingpins of the serial killings are not punished."