what does "jimmy marks"mean?
“Deputy Hanson logged your call to him at one-forty-three.”
“That’s right. We went into the kitchen, and I saw the alarm pad smudged, then checked the door and found fresh jimmy marks. And yeah, I’ve changed the code. Again.”
“And added backup,” Abra said, giving Barbie a rub.

Question

what does "jimmy marks"mean?
“Deputy Hanson logged your call to him at one-forty-three.” 
“That’s right. We went into the kitchen, and I saw the alarm pad smudged, then checked the door and found fresh jimmy marks. And yeah, I’ve changed the code. Again.” 
“And added backup,” Abra said, giving Barbie a rub.

Answer

It means Marks on the door lock , indicating it had been forced or tampered with

Also you can say 'The door had been jimmied'

it's a casual, slang expression for 'lock-pick'