Two Baton Rouge police officers died Sunday when their helicopter crashed into a sugarcane field, Louisiana authorities said.

The Robinson R–44 helicopter went out at 2 a.m. to help with a pursuit and never returned, local media reported. The aircraft’s disappearance wasn’t noticed for several hours, when a search was launched. The wreckage was found before 11 a.m.

The names of the officers have not been released.

“On behalf of the City of Baton Rouge, I extend my deepest condolences to the families and colleagues of the BRPD officers who tragically lost their lives,” Mayor–President Sharon Weston Broome said on Twitter.

Baton Rouge police officials did not immediately return a call seeking comment.

The National Transportation Safety Board said it is investigating the crash.