Two police shot dead and two injured in Louisiana

Police officers Brandon Nielsen (left) and Jeremy Triche were killed while investigating an earlier shooting

Two policemen have been shot dead and two others wounded in an early morning shootout near New Orleans.

The first attack occurred early on Thursday as an officer was shot for unknown reasons in an industrial plant car park, a sheriff said.

Two officers were then fatally shot at a trailer park while investigating the first incident.

Five people are in custody, some with gunshot wounds, police said. They do not think any suspects are still loose.

The two wounded officers are undergoing surgery at local hospitals, they added.

'Ambushed'

The two officers who died have been identified as Deputies Brandon Nielsen, 34, and Jeremy Triche, 27.

Louisiana Governor Bobby Jindal has ordered the state flags to be flown at half-staff over the state Capitol and all public buildings and institutions until sunset on Friday.

Sheriff Mike Tregre became tearful during a news conference as he described what happened.

The first shooting occurred around 05:00 (10:00 GMT) in the Valero refinery car park, he said.

Officers investigating the incident tracked reports of a speeding car and ended up in a trailer park.

They handcuffed a suspect and knocked on the door of a trailer when a person with a dog answered, said Sheriff Tregre.

"Another person exited that trailer with an assault weapon and ambushed my two officers," he added. "Two deputies were killed and a third was wounded."

The wounded officers are Michael Boyington, 33, and Jason Triche, 30. The Triches are said to be related.

State police spokeswoman Melissa Matey told CNN that two of the deputies had been working off-duty and the other two were on duty.