Three Chinese men detained over the kidnapping of a Japanese man here all speak fluent Japanese, informed sources said Sunday.

The police in Shenyang, Liaoning Province, are continuing to question them and are also interviewing Eizaburo Yamanaka, 66, a former trading company employee from Tokyo found safe Saturday, two days after he went missing, the sources said.

The Shenyang police are expected to look into whether there was any contact between the suspects and Yamanaka before the kidnapping as well as try to find out more about a man who made threatening calls to the victim's home in Tokyo, they said.

Compared with people in other parts of China, residents of Liaoning Province and other parts of northeastern China are more likely to speak some Japanese due to historical factors, but not necessarily fluently.

Yamanaka, who lived in Shenyang until he was 8 years old, told police he was touring the city alone and was kidnapped by the three Chinese on arriving at Shenyang airport Thursday morning to head back to Japan, Japanese police said Sunday.