HARBIN - A man killed himself on Wednesday morning while adjusting a homemade bomb, according to police in Harbin, Northeast China's Heilongjiang province.

Wang Haiou made the explosive to kill his ex-girlfriend and himself, police said.

Wang, from Jixi city, entered the sales center of Shimao River New City Community in Songbei district and asked to use the bathroom.

He entered the bathroom on the first floor, and a few minutes later an employee heard a blast. Employees then found the man was dead.

"Nobody was near the bathroom, so there were no other casualties," said Zhou Mengxing, a manager at Harbin Shimao River New City Development and Construction Company, the community's estate developer.

"Wang Haiou worked as a security guard for Jingyang Property Management Company. He had left the company in March last year."

Wang was in his mid-20s, Zhou said.

Wang was holding a detonator in his right hand and his abdomen was burst open, police said.

He had checked into a hotel in the Daoli district, and police found a letter and materials to make a bomb in his room. In the letter, Wang said he wanted to kill himself and his ex-girlfriend, an employee at the sales center who broke up with him.

Wang carried the explosive as he looked for the woman on Wednesday morning, but he could not find her.

Police are still investigating.

An employee of Jingyang Property Management Company refused to comment when reached by China Daily in the afternoon.

According to information on its official website, the private company was established in 1999 and has about 1,000 employees.

This property management company has been providing service to the Shimao River New City Community since 2007, said Yin Shusheng, 67, a resident and member of the property owners' committee.

There are about 2,000 households in the community.