Can someone steal keys for DNA?

Hi,

Looking for some advice regarding a friend who I'm worried about.

He was out with his son at a seaside resort recently, someone happened to be there from his home town who recognised him and said hi to them both.

Didn't think much of it, however, later that day he discovered that his keys were missing and they were in his shorts back pocket, he can be clumsy but he suspects they might have been stolen, but obviously is not sure.

Him and his son were stranded and had to stay in a bed and breakfast that night, he had to also pay out a lot of money for a locksmith to get into his car and to get a replacement key, and then even more to get another locksmith out to break into his house and replace the keys.

For some reason his gut said to him recently that he felt like someone might be keeping tabs on him, not sure why as he's a decent guy who is quiet and keeps himself to himself, hasn't been in any trouble whatsoever for over 25 years.

Feel that he's worried that he might have been targeted and his keys stolen, for what reason I don't know, but I suppose with someone's keys you could set them up for something couldn't you, I have tried to offer reasurrance that it is unlikely that someone would have known he was in a town an hour a half away and happen to be there at the same time and swiped his keys, that would have to be a very targetted thing to have something like that take place, and would have to have been tracked or followed.

He isn't happy that his son was very stressed due to the keys going missing and them having to wait until the following evening to be dropped home with no clean clothes to change into and the hassle and cost of replacing all the keys.

Would someone steal keys purely to obtain DNA or to set someone up, or possibly just to cause a massive amount of stress and inconvenience to that person?