Post by DarrenIMDB.com says Pete the Dog was poisoned in 1930.
Another site says he was killed by someone who put broken glass in meat.
Which is true?
IMDB is worse for facts than even Wikipedia. It appears the best answer
is, we don't know what happened to Pete the Pup. This is from
truthorfiction.com:
Pete the Pup -- He was poisoned by an unknown assailant--Unproven!
There were actually several different dogs used through the years as Pete
the Pup, the canine star of films. There are several reports that the
original Pete the Pup was poisoned by someone who gave him meat laced with
glass. There is also an urban legend that Pete the Pup was buried with
Alfalfa but we've found no evidence of that and Pete the Pup died long
before Alfalfa. Alfalfa loved hunting and apparently there is a dog on his
tombstone that reflects that so that may have been a part of what prompted
the urban legend about Pete the Pup.