“Is there life after death? Trespass here and find out” is an anti-trespassing sign (suggesting that trespassers will be shot) that has been printed on many images. The signs have been cited in print since at least 1980.
 
       
29 May 1980, Atlanta (GA)

, “World Beats Path To Werbell’s Door In Cobb County” by Carol Reuben, Cobb Extra, pg. 4G, col. 2:
“I (Mitch Werbell—ed.) have a sign: ‘Interested In Life After Death? Trespass Here.’”
   
26 October 1980, Chicago (IL) Tribune, “Tutor for aspiring killers” by Bill Shaw, Magazine sec., pg. 42, col. 3:
A sign on the front door of Taylor’s home says: “Is there life after death? Trespass and find out!”
   
31 May 1981, The News-Leader (Springfield, MO), “Car’s noise emphasizes gag letter’s arrival” by Mike O’Brien, pg. 1B, col. 3:
A sign in his window warns ominously: “Is There Life After Death? Trespass Here and Find Out!”
 
15 January 1982, Washington (DC) Post, “The Hidden World of Devil’s Hole” by Lloyd Grove, Weekend sec., pg. 40, col. 1:
IS THERE LIFE AFTER DEATH?
TRESPASS AND FIND OUT!
 
10 August 1983, Morning Advocate (Baton Rouge, LA), “Smiley Anders’ Baton Rouge, pg. 1B, col. 1:
This led, she said, to suggestions for signs to put on doors to discourage burglars. Such as: (...) and “Is there life after death? Trespass and find out.”
   
Google Books
Flying in Coffin Corner
By Robert L. Thompson
Sahuarita, AZ: Whitewing Press
1995
Pg. 170:
The chaplain’s roommate wasted no time in hanging a sign in front of their new home: “Is there life after death? Trespass here and find out!”
       
Google Books
The Road to Optimism:
Change Your Language, Change Your Life
By J. Mitchell Perry and Rick Griggs
San Ramon, CA: Manfit Press
1997
Pg. 169:
Instead of saying, “No Trespassing,” you could have some light fun and say, “Trespassers will be eaten,” or “If you are here today, you will be found here tomorrow,” or even “Is there life after death? Trespass here and find out.”
 
Google Books
Strange Places, Questionable People
By John Simpson
New York, NY: Macmillan
1998
Pg. 515:
There used to be a sign outside one house that said, ‘Is There Life After Death? Trespass Here And Find Out.’
   
Google Books
Unquiet Ghosts:
A Novel
By Glenn Meade
New York, NY: Simon & Schuster
2017
Pg. 140:
I noticed a rusted metal sign nailed to a piece of two-by-four, stuck right in the middle of the lawn: “Is There Life after Death? Trespass Here and Find Out.”
 
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4:53 AM - 23 Jul 2018