Get the in-game lockpick from the Black Market
A locked trunk can still be a loot target in ROB RUN. Purchase a lockpick from the Black Market and use it to access another player's vehicle trunk, including the trunk of a police car. That is the tool-and-target combination established by the developer's help page.
For ROB RUN how to lockpick car trunks, the essential preparation is obtaining the correct in-game item. The official ROB RUN trunk-lockpicking instructions identify the Black Market as its purchase source.
Target the trunk without assuming a specific minigame
Once you have the lockpick, the supported target is another player's vehicle trunk. Police cars are explicitly included, so a vehicle's police role does not make its trunk exempt from this mechanic.
The official instructions do not specify a hotkey, lockpicking minigame, opening timer, success percentage, or number of uses per pick. Follow the interaction instructions displayed by your game rather than assuming a particular control sequence or tool lifespan.
Also avoid budgeting around an unverified fixed lockpick price. The item source is established, but its cost and any transaction details are not supplied in the published trunk instructions.
Distinguish trunk looting from taking the whole car
Opening a trunk does not establish ownership of the vehicle. In the developer's October 2 FAQ, trunk raiding is described as something players can do anywhere in the city, while taking another player's car is tied to a much larger base-raid outcome.
That FAQ says taking vehicles parked on another player's property requires a raid that completely wipes the base, using an extremely rare raid item. This is a separate mechanic from using a lockpick on a trunk. Do not expect a successful trunk interaction to give you the car or its ownership key.
The same distinction matters when using your own vehicle: its trunk should not be treated as untouchable storage merely because the car belongs to you.
FAQ
Where do I get a trunk lockpick?
Buy the in-game lockpick on the Black Market.
Can I open a police car's trunk?
Yes. The official trunk guide specifically includes cop cars among the vehicle trunks that lockpicks can open.
Does opening the trunk let me steal the car?
The sources describe trunk looting and vehicle acquisition as separate mechanics. The developer's FAQ ties taking another player's parked vehicles to completely wiping their base with a rare raid item.
How long does lockpicking take?
The available official trunk instructions do not provide a duration, success rate, or button sequence. Use the prompts shown in your game.