Chinese e-commerce giant JD said on Monday its founder and CEO, Liu Qiangdong, has returned to China and resumed work after his arrest in Minneapolis in the United States on suspicion of criminal sexual conduct. He was later released without charges or bail.

The Foreign Ministry said on Monday it is looking into the arrest of a Chinese citizen in the US. Ministry spokeswoman Hua Chunying told a news conference in Beijing the Chinese Consulate in Chicago is "closely following the relevant situation" and trying to verify the facts.

JD's American depositary receipts traded in Frankfurt, Germany, slumped 4.69 percent to 25.63 euros ($29.70) after the market opened on Monday. The US stock market was closed on Monday for the Labor Day holiday.

The company said in a statement on the social media site Sina Weibo on Sunday that Liu was falsely accused of sexual misconduct while in the US on a business trip.

It said local police found no misconduct and that Liu would continue his trip as planned. "We will take necessary legal action against false reporting or rumors," JD said.

Jail records from Hennepin county, Minneapolis, show Liu was arrested at 11:32 pm on Friday and released at 4 pm on Saturday, pending further investigation and possible criminal charges. The jail records do not provide details of the alleged incident.

Minneapolis police spokesman John Elder said he could not provide any details because the investigation is considered active. He declined to say where in Minneapolis Liu was arrested or what Liu was accused of doing, The Associated Press reported.

The University of Minnesota said Liu was a student in its doctor of business administration program, primarily held in Beijing in partnership with Tsinghua University. The students were in Minneapolis last week as part of their training, Reuters reported.

Chinese social media was abuzz over Liu's arrest in the US, which was the most discussed topic on micro blogs on Monday morning.