Police in Perth say they have recovered all military items that were in a stolen car involved in a fatal crash on Friday.

The car, allegedly stolen by 18-year-old Zachary Smith earlier in the week, crashed into a cement truck which then hit another car, killing a 46-year-old woman.

Mr Smith was arrested on Friday night and faced court yesterday, where it was revealed the stolen car contained several Defence Force items including ammunition, body armour and two stun distraction grenades.

Police prosecutors told the court the two stun grenades had not been recovered and Mr Smith had refused to tell police where they were.

The magistrate remanded Mr Smith in custody because police argued his access to the equipment posed a risk to the community.

However, WA Police now say they had recovered all of the items before his court appearance.

The Department of Defence has not commented on how the items came to be in the car but says it is assisting police with their investigation.