The relatives have plenty of good reason to act distant toward those with a criminal mindset. They should protect their assets, and caution others especially if they have been a victim of a shady relative's schemes in the past. As much as some would like for things to be left in the past, it can be quite difficult to forget about offenses when they are still ongoing. I think of deceitful family members who repeatedly let loved ones down. Then after some time passed (out of sight, out of mind), they acted as if all was okay and they had changed. But the reality was, these liars, thieves, and murderers only got better with their acting skills.
The family charlatans who boast how much they love family usually have two faces. The one that everyone sees (good guy) and the one a few can see (bad guy). Enabling family members will try to protect the one who thinks himself to be honest and true (a changed man or woman) by singing his or her praises for all to hear. They will talk of how much the so-called righteous relative did in the past for the family. They will boast about all the service they have received from the individual. These enablers might go so far as to give the deceivers many gifts while hoping that others will hop on the bandwagon.
It is unfortunate but rarely do people with a long history of lying, stealing, and fighting change. They might grow older and get slower, but their mentalities are still very selfish and downright evil. Some will go into hiding for a time while hoping that those around them are convinced they have changed before coming around family once again. Others will be quite open about their misdeeds but all the while plot their next move. They hope that discerning relatives will see that things appear to be different with them even when it is apparent that there is no change.
Set some traps for sneaky relatives, interview others about their behaviors, and watch how these liars, thieves and murderers in your family operate for a time. Sooner or later what is in darkness will come to light.