Can I put a lien on estate property/trust?

Long story short, there’s an older couple that I knew and they passed. They had one son and three grandchildren. The grandkids fraudulently transferred properties and stole millions of dollars after the grandpa passed. When the grandma passed the son promised me if I helped expose all their wrongdoings, theft ect. Then I could have a property and money. Now it’s coming down to court time and I did everything for them, greed has set in and they are trying not to give me what we agreed on. Two of the three grandkids stole about $4k each from me as well. My question is, can I put a lien on the properties or the estate so I can get paid before probate court? Or how do I go about getting paid? Thank you for your help.