HONG KONG -- Hong Kong police on Thursday arrested a man accused of assisting another suspect in the gruesome killing of model Abby Choi, whose dismembered body parts were found in a refrigerator.

The arrest of the 41-year-old man brought the total number of people allegedly involved in the case to six. Officers believed the man, who worked in a yacht rental company, had attempted to help another suspect flee Hong Kong, police superintendent Alan Chung told reporters.

The gruesome killing of Choi, 28, has gripped many in Hong Kong and across the border in mainland China since the semi-autonomous southern Chinese city has a very low level of violent crime.

Earlier this week, Choi's ex-husband, Alex Kwong, his father, Kwong Kau, and his brother, Anthony Kwong, were charged with murder after police found her remains in a house rented by Kwong Kau in a suburban area of Hong Kong near the border with mainland China. Alex Kwong's mother, Jenny Li, faces one count of perverting the course of justice. All four were detained without bail.

Another woman who had been arrested for allegedly assisting other suspects in the case was earlier released on bail pending further investigation. Authorities believe she is in an affair with the ex-husband's father.

After a three-day search at a landfill, Chung on Thursday said officers could not find any substantial evidence and would cease their work there.

"Even though we can't find more, we've already secured some solid evidence," Chung said. "We will not give up any clue."

Choi, who had more than 100,000 followers on Instagram, disappeared Feb. 21, according to a report filed later with police.

She had financial disputes involving tens of millions of Hong Kong dollars (millions of dollars) with her ex-husband and his family, police said, adding that "some people" were unhappy with how Choi handled her finances.

While violent crime is rare in Hong Kong, the case recalls a handful of other shocking killings. In 2013, a man killed his parents and their heads were later found in refrigerators. In another infamous 1999 case, a woman was kidnapped and tortured by three members of an organized crime group before her death. Her skull was later found stuffed in a Hello Kitty doll.