The Vancouver Police Department has handed off its investigation into a mistaken identity assault case involving two of its officers.

Yao Wei Wu, 44, was badly injured by two plain-clothed officers responding to a domestic violence call on Jan. 21. The pair didn't know there were two suites in the residence -- and arrested Wu in error.

In a joint press conference with Police Complaints Commissioner Stan Lowe Friday morning, Vancouver Police Chief Jim Chu said Delta Police will now handle the case, adding that police officers are human and make mistakes.

"If we make a mistake we should apologize and look at it and make sure it doesn't happen again."

Chu personally apologized to Wu after the incident. He said part of the reason the case is being transferred is because Wu's lawyer, Cameron Ward, is already involved in a case with the department.

Don Davies, the NDP MP for Vancouver-Kingsway, said the investigation reveals structural problems in the police complaints process in British Columbia.

"Having the Delta police investigate the Vancouver police does not give the public the confidence that they need."

Davies said he's also concerned about the use of power.

"We had two police officers that beat someone up. Whether that person can speak English or not that's an inappropriate response."

In a letter sent to VPD officials Thursday, Ward said his client will sue the force for damages and personal injury. The letter also asks officers to cease contacting Wu.

Former provincial NDP candidate Gabriel Yiu said Wu has been off work since the assault and doesn't have insurance to compensate him.

The Office of the Police Complaint Commissioner is monitoring the progress of the internal investigation.