There is crime everywhere! What you need to determine is acceptable levels.
This is a real sticky subject and you're not likely to get a direct answer from agents, mostly because they are not suppose to say, they can provide you with information or better yet the source where to get this info.
If an agent tells you directly this is a low crime area and you get robbed or crime picks up, the likelihood of you suing them is high. The best advise I can give you would be to call or visit the Linden Police department and explain to them your situation and ask them on an off the record basis if the area has had criminal activity in the last year and to what degree.
Going to the source!
I live in Linden and know the answer but am hesitant to say especially without knowing exactly where by the park very large park. Try driving around with the windows down or taking a walk in the area at different times of the day and night to get a pretty decent idea in addition to the above suggestion.
Looking up crime statistics on websites wont be very helpful for this for a specific area, only to tell about a town in general.
If your looking to buy in Linden, give me a buzz and I'll help you find something nice in the least likely areas for you to get mugged but that's no guarantee either. (disclaimer) ;-D