This is an article that was written in November 2025 about a well-aged IED that was discovered in a backyard during landscaping at an address in Santa Rosa in January 2015. The gist of the write up is evidently to push speculation as to whether this could, in fact, have been The Zodiac's 'Buss Bomb' in situ. As to its size and design, it doesn't closely match anything from the drawing and description he gave in his April 1970 letter, but it was found in an area that was largely rural at the time in question, according to Tom.

The article also mentions the presumably well-known fact of bomb-making equipment having been found during a search of Allen's address in Fresno Street, Vallejo.

Although not claiming to be able to match the relevance of either of the above discoveries, I did come across a brief article from June 2011 that also cited "vintage explosives" having been discovered at a rented property in San Francisco, with a little more context added by NBC Bay Area here.

It may be that there are other such explosive finds around the Bay Area since 1970 and, if anyone has any stories or articles of this nature, perhaps you could post something on this thread?

My transcription (may contain errors):

PS. 2 cops pulled a goof abot 3
min after I left the cab. I was
walking down the hill to the
park when this cop car pulled up
+ one of the m called me over
+ asked if I saw any one
acting supicisous or strange
in the last 5 to 10 min + I said
yes there was this man who
was runnig by waveing a gun
+ the cops peeled rubber +
went around the corner as
I directed them + I dissap -
eared into the park a block +
a half away never to be seen
again.

The length is indeed 340 when spaces, line breaks and full stops are removed (leaving us with the 0-9, A-Z, "+" and "-")

>>> z340b_raw = """
... PS. 2 cops pulled a goof abot 3
... min after I left the cab. I was
... walking down the hill to the
... park when this cop car pulled up
... + one of the m called me over
... + asked if I saw any one
... acting supicisous or strange
... in the last 5 to 10 min + I said
... yes there was this man who
... was runnig by waveing a gun
... + the cops peeled rubber +
... went around the corner as
... I directed them + I dissap -
... eared into the park a block +
... a half away never to be seen
... again.
... """
>>>
>>> z340b = "".join(x for x in z340b_raw if x not in (" ", ".", "\n")).upper()
>>>
>>> print(z340b)
PS2COPSPULLEDAGOOFABOT3MINAFTERILEFTTHECABIWASWALKINGDOWNTHEHILLTOTHEPARKWHENTHISCOPCARPULLEDUP+ONEOFTHEMCALLEDMEOVER+ASKEDIFISAWANYONEACTINGSUPICISOUSORSTRANGEINTHELAST5TO10MIN+ISAIDYESTHEREWASTHISMANWHOWASRUNNIGBYWAVEINGAGUN+THECOPSPEELEDRUBBER+WENTAROUNDTHECORNERASIDIRECTEDTHEM+IDISSAP-EAREDINTOTHEPARKABLOCK+AHALFAWAYNEVERTOBESEENAGAIN
>>>
>>> print(len(z340b))
340
>>>

17x20

PS2COPSPULLEDAGOO
FABOT3MINAFTERILE
FTTHECABIWASWALKI
NGDOWNTHEHILLTOTH
EPARKWHENTHISCOPC
ARPULLEDUP+ONEOFT
HEMCALLEDMEOVER+A
SKEDIFISAWANYONEA
CTINGSUPICISOUSOR
STRANGEINTHELAST5
TO10MIN+ISAIDYEST
HEREWASTHISMANWHO
WASRUNNIGBYWAVEIN
GAGUN+THECOPSPEEL
EDRUBBER+WENTAROU
NDTHECORNERASIDIR
ECTEDTHEM+IDISSAP
-EAREDINTOTHEPARK
ABLOCK+AHALFAWAYN
EVERTOBESEENAGAIN

34x10

PS2COPSPULLEDAGOOFABOT3MINAFTERILE
FTTHECABIWASWALKINGDOWNTHEHILLTOTH
EPARKWHENTHISCOPCARPULLEDUP+ONEOFT
HEMCALLEDMEOVER+ASKEDIFISAWANYONEA
CTINGSUPICISOUSORSTRANGEINTHELAST5
TO10MIN+ISAIDYESTHEREWASTHISMANWHO
WASRUNNIGBYWAVEINGAGUN+THECOPSPEEL
EDRUBBER+WENTAROUNDTHECORNERASIDIR
ECTEDTHEM+IDISSAP-EAREDINTOTHEPARK
ABLOCK+AHALFAWAYNEVERTOBESEENAGAIN

68x5

PS2COPSPULLEDAGOOFABOT3MINAFTERILEFTTHECABIWASWALKINGDOWNTHEHILLTOTH
EPARKWHENTHISCOPCARPULLEDUP+ONEOFTHEMCALLEDMEOVER+ASKEDIFISAWANYONEA
CTINGSUPICISOUSORSTRANGEINTHELAST5TO10MIN+ISAIDYESTHEREWASTHISMANWHO
WASRUNNIGBYWAVEINGAGUN+THECOPSPEELEDRUBBER+WENTAROUNDTHECORNERASIDIR
ECTEDTHEM+IDISSAP-EAREDINTOTHEPARKABLOCK+AHALFAWAYNEVERTOBESEENAGAIN

A connection to z13?

I've noticed that if you reverse the lines in the above, there'll be a line that starts with "AEN" and the string "NAM" can be found further down (as part of "NAMSI", "NAME IS"?):

ELIRETFANIM3TOBAFOOGADELLUPSPOC2SP
HTOTLLIHEHTNWODGNIKLAWSAWIBACEHTTF
TFOENO+PUDELLUPRACPOCSIHTNEHWKRAPE
AENOYNAWASIFIDEKSA+REVOEMDELLACMEH
5TSALEHTNIEGNARTSROSUOSICIPUSGNITC
OHWNAMSIHTSAWEREHTSEYDIASI+NIM01OT
LEEPSPOCEHT+NUGAGNIEVAWYBGINNURSAW
RIDISARENROCEHTDNUORATNEW+REBBURDE
KRAPEHTOTNIDERAE-PASSIDI+MEHTDETCE
NIAGANEESEBOTREVENYAWAFLAHA+KCOLBA

Lines 4 to 6:

AENOYNAWASIFIDEKSA+REVOEMDELLACMEH
5TSALEHTNIEGNARTSROSUOSICIPUSGNITC
OHWNAM

z13 for reference:

AEN⊕⑧K⑧M⑧⊥NAM

Maybe z13 points to a section in this text or the equivalent positions in z340? What do you guys think?