As Karen Climer said, you don't have to disclose in Florida.  It is NOT a material fact.

See Florida Statutes 689.25

Serious Caveat: 

     "Well, I am going to disclose it anyway."  That might not be a good idea.   You, as a Listing Agent, especially as a Single Agent with a Fiduciary to that Seller, could DAMAGE your Seller.  By disclosing a murder, suicide, you could hurt the Seller's financial position, and/or negotiating petition.  

  My suggestion:  see an Attorney for legal advice, and have a thorough discussion with the Seller.  Get their position in writing. 

     Because if a Buyer asks, "I saw it in the news that a murder happened here", or "the neighbor told me the prior owner committed suicide") you need to know how to answer.

In California, we are required to disclose a death in the property within the past 3 years.

We are not required to disclose the cause of death although buyers seem to want all the details.  If it happens to be cancer, they want to know what kind of cancer.  That is simply none of their business. They died peacefully in their home.

If it happens to be suicide or murder, we are required to disclose what we know, material facts.  A murder and potentially a suicide could be considered as material.

In 1998, Massachusetts enacted the Stigmatized Property Law (Chapter 93, Section 114). This statute specifically states that brokers do not have a duty to investigate or affirmatively disclose murders, suicides, allegations of ghosts, or other possible stigmas.

Legally ok but ethically/morally?

That is not a disclosable item in our state. But if asked, we can't lie.

Not a material fact in Florida.  We don't have to disclose suicides, murders, deaths, ghosts on anything similar.

In states the require you to disclose deaths, I don't know how you do it.  In an old house, the odds are pretty high that someone died there at some point.  How is the agent suppose to figure out that someone died in their sleep in the house in 1948?

No requirement to disclose, buyer due diligence to discover.   However, I usually ask the seller if I can disclose, as if they talk to the neighbors and cannot live with the news, they will want to terminate the contract.  Might as well get this information out from the beginning.   I have sold several that have had deaths in the house.

In Utah, a seller does not have to disclose that a home was the location of a homicide, a suicide, a decontaminated methamphetamine lab or by a person with Aids.

If asked, it is best to be forthcoming.

Side story:

My Mom sold the house that my parents raised all five of us in 2000. My father passed from a stroke in the hospital ten years prior. She wasn't required to disclose that in California as he didn't die at home and was natural causes. The new owners contacted my brother in 2020 many years later claiming my father's ghost was in the home bothering them at night. My family had fruit trees: apricot, plum, oranges, two types of lemons, limes, pomegranate, pistachio.... I went with my brother to see our old house last year when they listed it for sale (not disclosing their ghost claim in the MLS) Pretty easy to figure the noises were rats in the attic who stored all kinds of food... ick.   Funny side note is how our memory tricks us - things I remembered about the house like the size of the pool shrunk.

Andrew,

Kathleen Daniels, Probate & Trust Specialist gave you the CA scoop.  A

A good Q!
AZ seller does NOT have to disclose a felony including murder or suicide in the house, anyone with HIV/Aids or anything not communicable by direct contact, or that the property is in proximity to a registered sex offender. 

I tell them talk to the neighbors before inspections are up. Wealth of info there LOL. Also, talk to the cops. And the sex offender registry is online. Couple of former agents on it!

California:

Death on the premises within the last 3 years must be disclosed. There are limited exceptions. A notorious death should always be disclosed. You know the neighbors will inform the new owner before the movers are done moving the new furniture in. Also, if asked about prior deaths, you must speak the truth...duh!

We do not have to disclose anything regarding deaths in a home in Oregon - even if there is a murder/suicide.  However, if someone asks about it to a listing agent and the listing agent knows, they are obligated to tell the truth.

Not a NY requirement to disclose however, if I'm asked and I know, I must. 

I had one listing once where the neighbor made sure she was outside for every showing to tell everyone so... it was definitely disclosed.

Not required.
HOWEVER, the machete massacre house was scheduled to close next day and buyers wanted to take another look. Neighbor introduced themselves and asked "Did you know........."
CLosing never happed, agent got press she didn't need.
SOLD 9 months later at a discount.
I advise buyers if this is a concern we should be looking at NEW CONSSTRUCTION and who knows what happed on that land 800 years ago.

Not a mandatory disclosure in Connecticut.

I am not aware of disclosure requirements in our area.

In IL we do not have to disclose.

In Texas, the question is ask in the Seller Disclosure. But only have to indicate if there was a murder or un-natural death!

According to the Texas Property Code, sellers aren’t required to disclose deaths on the property that resulted from natural causes, suicide, or an accident unrelated to the property’s condition.

However, murder does not fall into these categories. The Deceptive Trade Practices Act may require the disclosure of murders unrelated to a condition of the property as material facts a buyer would want to know before entering into a transaction.

TAR’s Seller’s Disclosure Notice includes a question about deaths other than those caused by natural causes, suicide, or an accident unrelated to the property’s condition.

no disclosure, but answer honestly if asked.

No ones business.  Mental illness is no different than physical illness so suicide is no different than cancer. Canada does not have a Predator's List either. 

While inquiring minds may want to know, in Illinois and Florida no requirement to disclose. So, zip it and more on!

Disclosable only if we are directly asked in both North and South Carolina.

How about you, Andy?

Three years for any death, unlimited for notorious deaths.  That type would be something major for example a Manson type of murder.  Anything that the neighbors would be speaking of should be disclosed just to be safe.

Not a required disclosure in VA, but if known, and someone asks about it, I'd tell them, or tell them where to look for that info unless seller have given me written instructions not to.

If recent or in the media, I tell. If old news, I stand ready to tell if comes up