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Is it theoretically possible to wipe/ reset/ access phones that are pattern protected?

Brother passed away . We have a LG v30, LG v40 and Samsung fold apart screen with stylus - the first two are his old ones - no sim jn them but all still have pattern protection on.

i tried hard factory reset from online, that supposedly could be done if forgot password etc , bs doesnt work on the LGs, plus the v40 needs to be turned off first before factory reset can be done but has pattern protection even for turning off.

Went to the actual provider today explained, but indian guy said 'privacy laws bla bla - nothing you can do, bc this protects the customers privacy' - i get what he says according to his policy and his co worker standing next to him listening in but how do cops and back street vendors get into a password protected phone and the back street venders reselling them after wiping them/ - Or dont they?.

PS not wanting to break any applicable laws - just a conversation on how it might be done in order to prevent it . /