Research crimes in your local area and find a victim of murder - someone who died badly; it's best if their murderer wasn't ever found. Don't choose your family member; choose someone different. Find out where they are buried.
Go to the graveyard with a small handshovel, a plastic baggie, five silver coils, and a bouquet of flowers. When entering the cemetary leave two silver coins by the enterance as payment for the spirits.
Get in a meditative and prayerful frame of mind and walk to the grave of the person who was murdered. Ask the spirit of that person if they will help you catch the murderer who killed your family member. Stay open because sometimes the spirits don't want to help - it's not often, though.
Ask this spirit to hunt the murderer down and hound him mercilessly until he makes a full confession - but ONLY if he's truly guilty. Ask the spirit to look into this man's heart to see if he is in fact guilty of the crime. If he's innocent asl the spirit to give you a sign and to help you both heal. Speak with all your heart.
Ask the spirit if you can take a small amount of thier grave dirt. If allowed, dig up a small amount from the approximate spot where the right hand would have been. Leave the remaining three coins in the hole and fill it back up. Thank the spirit and leave the flowers as a further offering.
There's lots of variations to this old-timey working. You can leave a photograph of your deceased family member in the hole. You can also leave a ransom note and/or the photo of the person who did the crime. Other offerings include whiskey. If you can't find a grave of a murdered person - or a willing murdered person - soldiers make good spirit helpers too for this kind of work.
Leave the cemetary and walk straight home (or drive), without looking back, without talking to anyone, and going a different route home. Take the graveyard dirt home with you and place it in a place of reverence.