Four people in charge of a center that cared for vagrants have been placed under "coercive measures" - a legal term that generally means detention - following the suspicious death of a teenager who had spent 45 days at the center in Shaoguan, Guangdong province, the city government said in a statement on Monday.

The cause of death of 15-year-old Lei Wenfeng, who had autism and died at the center in December, is still being investigated, according to the statement.

The local anti-graft authority is also looking into whether officials were involved in the case, as the center was a partly government-funded establishment, the statement said.

The Lianxi center was shut down on March 2 pending further investigation after a special task force established after Lei's death that the center was not authorized to be open.

Lei got lost in Shenzhen in August and ended up in Dongguan, another city in Guangdong about 83 kilometers north of Shenzhen, a week later.

As his left foot was hurt, Lei was treated at a hospital, spending one and a half months at a relief station in Dongguan before being sent to the Lianxi center in October.

After having lived at the center for more than a month, he began to lose his appetite and was sent to hospital again where doctors found he was suffering from typhoid fever. He died in the hospital on Dec 3, eight days before his 16th birthday.

Police had been unable to locate his family since his death, while his father, Lei Hongjian, who comes from Hunan province but lived with Lei Wenfeng in Shenzhen, had also failed to locate his son.

His father was eventually informed by a friend who had access to the provincial relief station system that his son was dead.

According to media reports, Lei Wenfeng was not the only person to have died after staying at the Lianxi center.

The government statement said that an investigation is underway to uncover the number of deaths linked to the center and the causes of the deaths.