Japanese police have admitted there were flaws in the security for former Japanese Prime Minister Shinzo Abe, who was shot dead in the southern city of Nara on Friday.
"It is undeniable that there were problems in the security," said Nara police chief Tomoaki Onizuka.
A gunman opened fire on Abe at a political campaign event - a crime that has profoundly shocked Japan.
Sunday's elections for the upper house went ahead as planned.
Voting began at 07:00 local time (22:00GMT on Saturday), just two days after Abe's assassination, and closed at 21:00.
Exit polls suggested the ruling Liberal Democratic Party (LDP), in which Abe was a leading and hugely influential figure, and its junior coalition partner Komeito were set to retain their majority.
A moment of silence for Abe was held at the LDP Tokyo headquarters as members waited for the results to come in, Reuters report.
Elections for Japan's less-powerful upper house of parliament are typically seen as a referendum on the current government. But a big victory for the LDP would strengthen the current prime minister's ability to push though his key policies, including a doubling of defence spending.
Police say the suspect, named as Tetsuya Yamagami, 41, held a grudge against a "specific organisation".
Japanese media quote sources close to the investigation, who say Yamagami believed Abe to be linked to a religious group which, Yamagami alleged, had ruined his mother financially.
