How to Prove Undue Influence or Lack of Capacity for a Will in Kansas

Short answer: To challenge a will in Kansas on grounds of lack of testamentary capacity or undue influence you need concrete, contemporaneous, or corroborating evidence that shows the testator did not understand the nature and effect of the will or that someone overcame the testator’s free will. Typical proof includes medical records, witness statements, documents or communications showing suspicious conduct, and evidence that a beneficiary controlled the process. Courts look at the total picture: mental state, relationships, suspicious circumstances, and who actually prepared and benefited from the will.

Detailed Answer

What the law treats as testamentary capacity in Kansas

Under Kansas probate law, a person making a will must have testamentary capacity when the will is executed. In simple terms, that means the person must:

Understand that they are making a will;
Understand the nature and extent of their property;
Understand who would normally expect to benefit from their estate (family/friends) and the natural objects of their bounty; and
Be able to form a rational plan for distributing property.

Capacity is assessed at the time the will is signed. A diagnosis such as dementia does not automatically prove lack of capacity; the key is whether the particular testator could meet the four points above at signing.

What the law treats as undue influence in Kansas

Undue influence occurs when someone uses pressure, coercion, manipulation, or isolation to overcome the testator’s free agency and secure a will that reflects the influencer’s desires rather than the testator’s true intent. Courts consider factors such as:

Whether the beneficiary had an opportunity to influence the testator;
Whether the beneficiary actively participated in preparing the will or procuring witnesses;
Whether the testator was isolated from family, friends, or independent advisors;
Whether the will results in an unnatural disposition (e.g., large gift to a caregiver when close relatives are excluded); and
Any sudden or unexplained change in the testator’s estate plan.

Types of evidence that help prove lack of capacity

Medical records around the time of execution (neurology, psychiatry, primary care notes, hospital charts).
Medication lists that show sedatives or drugs that impair cognition.
Expert medical or neuropsychological evaluations (retrospective opinions are sometimes used but are weaker than contemporaneous tests).
Witness testimony from people present at signing or who interacted with the testator close in time to the signing who can describe confusion, memory loss, or inability to understand basic facts.
Handwriting samples and forensic document analysis if capacity is in question because of incoherent or inconsistent signatures or language.
Video or audio recordings showing the testator’s mental state at or near signing.

Types of evidence that help prove undue influence

Evidence that a beneficiary prepared, drafted, or heavily directed the will’s preparation (drafts, emails, messages).
Records showing the beneficiary controlled the testator’s communications, visits, or access to advisors (logs, phone records, witness statements).
Large, unexplained transfers to the beneficiary around the same time as the will.
Evidence the testator was isolated from family or independent counsel during the will’s preparation (witness testimony, visitation records).
Witness statements that the testator expressed different intentions before the contested will.
Presence of suspicious circumstances at signing: rushed signing, signing while incapacitated, or beneficiary attending as the only witness.

How a Kansas probate court evaluates the evidence

Courts consider all of the above in the context of the entire record. A single piece of weak evidence rarely wins a contest—courts weigh patterns and corroboration. Signed, attested wills are presumed valid, so challengers must produce persuasive proof that capacity was lacking or that undue influence overcame the testator’s free will. You should expect the court to look at who drafted the will, who benefited, what medical evidence exists, and witness credibility.

Practical steps to preserve and assemble evidence

Act quickly. Medical records and memories fade. If a will is recently probated, move promptly to investigate.
Collect medical records, medication lists, hospital discharge summaries, and doctors’ notes around the time of signing.
Identify and interview witnesses who saw the testator in the weeks before and after execution (friends, family, caregivers, bank staff, notary or attorney involved).
Preserve original documents, drafts, emails, texts, and any recordings related to the will’s preparation.
Look for contemporaneous statements by the testator about their intentions—these are powerful when they contradict the contested will.
Consider hiring a probate attorney promptly to assist with subpoenas, preservation letters, and expert retention (medical or handwriting experts).

Where to find the Kansas statutes and procedural rules

Kansas wills and probate rules appear in Chapter 59 of the Kansas Statutes. For the statutory framework about wills in Kansas, see the Kansas Revisor of Statutes: K.S.A. Chapter 59, Article 6 (Wills). For probate procedure and contests, review related sections in Chapter 59 and local probate court rules (Kansas judicial branch website).

Helpful Hints

Do not confront the testator or the beneficiary in ways that could destroy evidence. Let an attorney advise you on appropriate contact.
Time matters. File a probate contest quickly after discovering the will you believe is invalid. Delay can forfeit rights or make evidence harder to get.
Gather independent witness statements early—memories fade and witnesses relocate or die.
Medical records are often the most persuasive evidence of incapacity. Request them immediately (with a records release or via an attorney’s subpoena).
Look for patterns: a caregiver suddenly receiving a big gift combined with isolation and control over visits is more persuasive than any single item alone.
Keep detailed notes about who you talk to and what you learn. Dates, times, and specifics help later when building a case or giving information to counsel.
Speak to a probate attorney experienced in will contests. They can evaluate whether the available evidence is likely to meet the burden required in court and can pursue subpoenas and experts for you.

Disclaimer: This article provides general information about Kansas law and is not legal advice. It does not create an attorney-client relationship. For advice about your specific situation, consult a licensed Kansas probate attorney promptly.