How do I get my mothers estate from my step-father?

My mother passed away a little over a year ago and my step-father has simply fell off the face of the earth. He has been doing everything my mother said he would, such as selling property and not staying in touch with anyone.

They were married for over 20 years and my mother had a lot of investments. Is there any way that I can get my share of what my mother had in financial investments from my step-father? Do I have any legal right to any of her estate?

If your mother had a will, any individually - owned assets will pass according to the will. If you have not already done so, get a copy of the will if it was probated.

In many cases, assets owned by husband and wife are jointly owned. If, upon marriage, your mother changed ownership of her individual assets into husband and wife registration (either joint tenants with right of survivorship or tenants by the entireties), then that property belongs to the surviving joint owner.

If the will was probated and your step-father was appointed personal representative of the estate, and you were named as a beneficiary under the estate, you can have him removed as personal representative if he had not properly administered the estate. You can force him to do an accounting, and if he has converted estate assets, you can seek to recover either the assets or their value from him.

Yes, you may have rights. However, what you need to do now is to hire a probate lawyer to look after your interests. You will not be able to do much on your own.

Unless otherwise stated by a will you step father being the spouse is the next of kin.

You should get a lawyer ASAP. You likely have rights unless she wrote a will or trust in which she left you nothing.
PS - I think smedric is wrong.

you need to contact a attorney.. if she only had a will it has to go through probate and you can contest it up to a certain date
if it was a trust.. it cannot be contested and its given to the person/s listed in the trust

This all differs according to state

see an attorney

you have a legal right to whatever her will left you. If she had no will you need to go to your probate court in your county and get a lawyer soon.