Updated

The family of a Chinese woman and her two children who were among the victims of a tourist boat disaster off the Thai resort island of Phuket are demanding "justice," saying Saturday that the tragedy was caused by human error and could have been avoided.

Chen Wei, a businesswoman from Chongqing province, said videos and messages sent by her sister Chen De Qiong to the family's WeChat group just before the boat capsized on Thursday showed strong waves and passengers not wearing life vests.

The sister, Chen De Qiong, a 47-year-old doctor, arrived in Phuket on July 1 for a long-planned vacation with her 12-year-old son and 21-year-old daughter, Chen Wei said.

The body of the daughter, Xing Yu Jie, was recovered Friday. Chen Wei and her brother-in-law Xing Yong arrived in Phuket on Saturday afternoon after an overnight flight from Chongqing, and later identified the body of Chen De Qiong, which had been retrieved earlier in the day at a Phuket hospital. The son, Xing Hao Ran, was among the missing. Dozens died in the disaster.

The boat was carrying 105 people, including 93 tourists, most of them from China, when it capsized and sank after it was hit by 5-meter (16-foot) waves.

"I can hear the voice of my daughter screaming," Xing Yong said while transiting at Kuala Lumpur airport, as he showed the video to an Associated Press reporter. "You can see that nobody wore life jackets."

The short video clip, taken at a section of the boat's cabin, shows the boat tilting, with rough waves seen through the windows. A passenger tumbles down the aisle as belongings fall on the cabin floor, and a voice is heard shouting.

"It's shaking violently, and I'm feeling very dizzy," Chen De Qiong wrote to her family. "I want to go ashore immediately," she said in another message, saying her son was feeling ill.

Chen Wei said the boat company ignored warnings of bad weather and failed to take adequate measures to ensure passenger safety. She said the video showed that glass windows in the boat cabin were sealed but they should have had latches so that they can be opened to allow passengers to swim out in an emergency.

Despite rough waves, the boat didn't stop and kept sailing, Chen said.

"Three out of a family with four members gone. How would you feel about it? Which family can bear such a blow?" she said.

"There are loopholes everywhere that caused this tragedy. ... I just want to seek justice for my family. This is not a natural disaster. This tragedy is man-made and could have been avoided," she added.

She said the vacation was planned as a celebration for her niece, who had just graduated from university, and her nephew, who is about to enter high school.

"A beautiful family gone like that, just like in a dream," a distraught Chen said.

"When my niece was found yesterday, she had no life signs — her passport helped identify her body," she said. "Our biggest hope is to find my sister and nephew."

Chen Wei had spoken to the AP on the plane. Upon arrival in Phuket, the family was ushered to the hospital, where Xing Yong identified the body of his wife through photographs.