can a CSI specialist determine that a lock has been picked?

[robertgeo]

Once a lock (say a deadbolt cylinder pin-and-tumbler on a residential door) has been picked, is there any way a crime scene specialist who removes the lock and examines it in a lab, can determine that it was recently picked? Scratches on the tumblers, markings made by the picks or tension wrench, etc? Would a microscope be able to detect recent markings by picks? I am a crime & mystery book-writer researching this possibility. Thank you for you help.

[mbell]

In short, yes.

Obtain LSS/LSS+ if at all possible - The only in depth text on lock forensics I've found.

[Romstar]

Upon examining a lock, you can tell if it has been pick within the last six months I would say. Sometimes longer.

As you insert the key, you scratch the interior surface of that lock. However, those scratchs are always in line with what you would expect from a key.

Picking on the other hand will produce deeper, and more random scratching on the pin surfaces, as well as the sides of the lock. Also, because of the size and shape of the pick, it will tend to produce metal shavings where the key would not.

Depending on the material used to make the pins, some residual material from the pick may be left behind. This material could be picked up by treating the pins and lock plug to a mild acid solution. The materials will sperate, and allow identification via spectrograph.
The resultant material will not allow identification of the pick however, because most picks are made from the same material.

Using a mechanical pick in a lock will result in denting of the pins. The dents will be minor, or major depending on the complexity of the lock, duration of pick insertion, and the force the mechanical pick was set at durring it's use.

In addition, it is not uncommon to find aditional scratching on the face of the lock. However, one would assume where surpetitious entry was the desired result, they would be more careful.

In essence what you are looking for is scoring in the lock that is inconsistant with the normal usage of the key. This scoring results from the tension wrench, and the pick in particular.

Here is the real key however. If you are writing about crime, it is expected that a criminal even has occured behind the locked door. Without evidence of forced entry, this results in one of only a few assumptions.

1. The perpetrator was allowed in.
2. The perpetrator had a key.
3. The perpetrator used some sort of bypass technique. Anything from shimming the door, to picking the lock.

Try not to limit yourself to the complex. Often crimes are commited at the spur of the moment. This means that in many cases, the techniques will be less than elegant.
If we are talking about a complex staged event, there still sometimes arrises unexpected situations. It is often these events which lead investigators to unraveling the crime, and finding the perpetrators. The insomniac neighbour, the 3am jogger, the forgotten sanitation worker.

Good luck with your writing,
Romstar

[CaptHook]

Romstar.... good post man.
Chuck

[Mad Mick]

Perhaps Rom should start writing......that's another excellent post as always.

[robertgeo]

Thank you Rom, exactly what I was looking for.

[mattc]

I'm no expert on lockpicking, but while online recently I found a PowerPoint slideshow form a talk by Marc Tobias (?) in April last year, if I remember it was at Cambridge University.

Some of the slides show close-ups of pins which have had various tools used on them- picks, pick gun, impact picks (electric pick gun, I imagine).
Very interesting and hopefully of some use. If I ever find it again I'll post the address or whatever. It makes me wonder what the presentation was like in person

[Romstar]

Mr. Marc W. Tobias lectured on Tuesday 29th of April, 2003 at Cabridge University during a security seminar series.

Information concerning the lecture, and a link to the Power Point slides are located here:

http://www.cl.cam.ac.uk/Research/Securi ... 04-29.html

Enjoy the information. Despite the fact that notes are not included with the slides, I believe there is a lot of information that can be gleaned from these slides.

Romstar

[Chucklz]

I know that in a novel it is a moot point, but I thought I should still add this. A forensic investigation can show if picking has been attempted. While in most cases in which an investigation takes place, it is assumed that picking resulted in entry, in some cases it may not. Definately an interesting plot twist.