Crews pulled a ninth body Sunday from the wreckage of a Glasgow pub reduced to rubble when a police helicopter crashed into it Friday night. 

Scotland First Minister Alex Salmond told the BBC Sunday that 12 people were still hospitalized as a result of the wreck, with three still in critical condition. A memorial service for the victims was held Sunday at Glasgow Cathedral, with eight candles lit in memory of the eight people whose deaths had been confirmed at the time. 

The helicopter crashed into The Clutha club in Glasgow, where more than 100 people had gathered for a concert by a local ska band. 

Emergency officials are still searching the crash site for bodies while working to remove the aircraft's wreckage.

"This is a painstaking process which we expect to take some time," said Police Scotland Deputy Chief Constable Rose Fitzpatrick. "Until we remove the helicopter we cannot be sure what we will find."

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Investigators also are looking into what could have caused the helicopter to go down.

Officials said Sunday the aircraft was on a police operation and returning to Glasgow when it crashed, but declined to provide more details.

Police Scotland officially identified the three people killed on board the helicopter as Police Constable Kirsty Nelis, 36, Police Constable Tony Collins, 43, and civilian pilot David Traill, 51.

Two of the six people who died inside the pub have been identified as Samuel McGhee, 56, of Glasgow, and Gary Arthur, 48, of Paisley.

The Associated Press contributed to this report.