LILLOOET, B.C. -- A man suspected in a violent assault at a First Nation band office in the British Columbia Interior is dead after an attack that injured 10 people.

Michaela Swan with the Interior Health Authority said late Wednesday that five of the patients remain in hospital, two of whom are in critical condition, two in serious condition and one dealing with non-life-threatening injuries.

"All the patients will remain in hospital until they're medically cleared to go home. It's really hard to speculate at this point in time," she said.

"There certainly are some pretty serious injuries involved and we're monitoring the situation closely."

Swan said five other patients have been released from hospital.

RCMP said they were called just before 8:30 a.m. Wednesday to a report of a man with a weapon at the Bridge River Band Office near Lillooet.

When police arrived they found the suspect already restrained.

"RCMP members arrested the male but were unable to transport him as he became unconscious and unresponsive," police said in a news release.

The officers started CPR, but resuscitation efforts were unsuccessful and the man was pronounced dead at the scene, police said.

The injured people have been taken to hospitals around the region.

Coroner Barb McLintock confirmed one man died in the incident but couldn't provide further details. The B.C. Coroners Service was sending a team to investigate, she added.

An emergency worker who didn't want to be named said the man apparently attacked one person with the hammer, and when others in the office went to help they were also beaten.

Because the man died while in police custody, the Independent Investigations Office is now involved with the case.

The office said it was notified of the incident about 11:30 a.m. and its investigators were slated to arrive later Wednesday, when they would examine the actions of officers related to the man's death.

"Standard investigative activities include locating and interviewing any witnesses and collecting evidence from the scene," said a news release.

The office said it would not provide any details about the man who died while in custody, nor release further updates.

It said the RCMP will maintain jurisdiction over the investigation into the initial attack by the man.

Bridge River Indian Band Chief Susan James issued a statement, saying her immediate concern was to ensure that the families involved in the tragedy were being helped.

"Our attention now will be on the healing work we need to do," the statement said. "This tragedy has put our community in shock."

Bridge River is a tiny aboriginal town located about nine kilometres northwest of Lillooet.