What does PA law say about finding a stray dog?

[maggiebridget09]

Last summer, my friend found a stray Yorkie at a busy intersection, while he was riding his bike. (My friend rides a bike a lot because he has poor circulation in his legs and feet due to diabetes.) He went to a several businesses and residences in the area, including a convenience store, to see if anyone knew who the dog belonged to. He left his name and number with several people in case anyone was looking for the dog. He, then, took the dog home.
We live in an area that doesn't have a municipal dog pound, so many stray animals end up at the local shelter. On the third day at my suggestion, he called the local shelter to ask if anyone with a missing Yorkie had called. He was told that no one had inquired about a dog fitting that description. It turns out that where he found the dog is over the county line. He should have called the ACO for that county. Anyone could've made this mistake.
After he had the dog for 4 days, the police showed up at his house to arrest him for not getting the dog back to the owners in "a reasonable amount of time"---I kid you not this is what was written on his citation!!!! Apparently, there was poster in the convenience store advertising a $3000 reward for the dog that was posted the day after he found the dog. One of the employees gave my friend's info to the dog owner. The dog's owner called the police.
While my friend still had the dog, he told at least 15 people, myself, included that he had found this dog and that he was trying to find out who it belonged to. He had written statements from all of us including the shelter worker, who took his phone call. Mind you most of these people don't know my friend personally. He got the statements from the people he spoke with at the businesses that he visited the day he found the dog.
The magistrate refused to hear the case. Now, it's going to a jury trial in Dec. Yesterday, the prosecutor's office offered a plea bargain---plead guilty and take community service and ARD classes. His attorney told him not to take it. My friend wouldn't have accepted the plea bargain anyway. However, if he loses his case, he's looking at fines and possibly jail time.
I know this story sounds crazy. But, I swear it's true. I saw the citation myself. Note: Several years ago, my indoor cat went missing for about a week. One day I saw him sitting in a neighbor's window.(BTW, when my cat went missing, I asked the neighbor if she had seen him and she said no.) The neighbor refused to give my cat back. I called the police. The police told me that since my cat was off the property it was considered a stray and therefore my neighbor legally didn't have to return my cat. Eventually, she did give my cat back, but only because young daughter was so upset.
I'm sorry that this post is so long, but I wanted to supply the facts...Can someone tell me what the law actually is for reporting and/or returning stray dogs?