Betsy Aardsma (July 1947-November 1969) was killed by a single knife wound to the heart in the campus library of Pennsylvania State University by an unknown assailant or assailants between 4.30 and 4.45pm on November 28th 1969. A desk clerk was alerted by somebody shortly after the stabbing stating "Somebody better help that girl", but unfortunately the young woman was critically wounded and was pronounced dead on her arrival at hospital. This case still remains active nearly 47 years later, with Pennsylvania police still seeking fresh information.
Zodiac enthusiasts have put forward the idea that this crime could be the work of the notorious killer, based upon certain criteria, in particular the apparent emphasis the Zodiac placed on dates.
The Confession Letter sent almost three years prior to Betsy Aardsma's death, was mailed to the Riverside Police and Riverside Enterprise on November 29th 1966 and the Joan Webster disappearance and murder on November 28th 1981, exactly twelve years after this crime has been put forward as another possible Zodiac crime.
 http://joanwebstermurder.yolasite.com/

Contact here with any info on the case
Rockview State Police Barracks, 
Trooper Leigh Ann Barrows, 
(814) 355 7545. 

But the only thing linking the Betsy Aardsma killing to the Zodiac is a date, a similarity to the appearance of Cheri Jo Bates, both women were young college students with an independent mind, along with the library connection, albeit each crime was perpetrated at different times of the day, with one inside the library and the other in an alleyway beside the library. 
It has also been shown that a possible overlap of Betsy Aardsma and Theodore Kaczynski occurred when Betsy spent time at Ann Arbor from 1966-67, which coincided with Kaczynski for one year, plus he was also spotted in the Pennsylvania State Library on November 27th 1969 just one day prior to her murder according to an eyewitness.
But despite tenuous links to the Zodiac, it falls short on a number of issues, namely the Zodiac attacks tended to be committed in isolated retreats with limited possibility of capture such as Lake Herman Road, Blue Rock Springs Park and Lake Berryessa. The only confirmed deviation to this was the taxi cab murder of Paul Stine, but as many have conjectured  this may not have been a planned murder, but more of an impulse killing.
Betsy Aardsma was killed in the daytime at around 4.45pm, with high risk involved and although the Zodiac always laid claim to more killings than could be accounted for, no reference to this crime was evident in any of his subsequent correspondence and just because a murder was committed around the Zodiac timeline is no proof of his involvement.
Richard Haefner became a prime suspect in the case and details about Haefner can be found following the links below, that includes a composite sketch of a potential suspect from the library that afternoon. 
READ THIS ARTICLE ABOUT BETSY AARDSMA FROM THE POST GAZETTE IN 2009
​http://zodiackillersite.com/viewtopic.php?f=47&t=451​

(19th August 1956-28th November 1981)
Joan Lucinda Webster, a 25 year old Harvard graduate, disappeared after her arrival at Boston's Logan International Airport, on 28th November 1981, and her remains were discovered nearly nine years later in April 1990 in Hamilton, Massachusetts.
The cause of her death remains undetermined and nobody has been charged with her supposed abduction and murder.
The case is constantly kept alive by determined individuals keen for a resolution to this 32 year old murder mystery.
http://joanwebstermurder.yolasite.com/