LONDON (AP) — A police officer has been arrested in connection with a woman who went missing in London last week, Britain’s Metropolitan Police said. The force said Wednesday the fact that the man is a serving police officer is “shocking and deeply disturbing.”

Police said the officer was arrested late Tuesday in Kent, southeast of London, as part of the investigation into the disappearance of Sarah Everard, a 33-year-old marketing executive who vanished while walking home from a friend’s apartment in south London on March 3.

The officer was not on duty at the time of Everard’s disappearance. Police did not say what he was detained for, or whether he knew Everard. The force said he was arrested along with a woman who has been held on suspicion of assisting an offender.

When asked whether police believe Everard is still alive, Assistant Commissioner Nick Ephgrave said detectives were searching as hard as they can and “really hope that is the case,” the BBC reported.

“This is a serious and significant development in our search for Sarah and the fact that the man who has been arrested is a serving Metropolitan Police officer is both shocking and deeply disturbing,” Ephgrave told reporters.

Detectives were searching a house and woodland in Kent following the arrest of the officer and the woman. The officer has been taken into custody at a London police station.