In order to rule a 'person of interest' in or out, it is always helpful to examine that person's natal chart, to ascertain whether the chart owner's energy patterns predispose him/her to perpetrating the crime.
Here is JP's natal, cast for sunrise and relocated to Salt Lake City, UT:
JP's SUN and MOON are both seriously afflicted which immediately gives a sense of trouble.
SUN sesquisquare MOON (relationship difficulties)
SUN sesquisquare MARS (poor energy management; inappropriately aggressive)
SUN opposite SATURN (possible rejection of responsibility/ poor integration of responsibility; feels oppressed; feels 'authority figures' are 'out to get him'; in other words, his problems are caused by others rather than self)
SUN semisquare NEPTUNE (possible confused concept of reality; lives in a 'strange reality', lacks perspective)
SUN square CHIRON (possible damaged sense of identity, particularly because Chiron is in Aries (the self) in this chart)
MOON square MARS (relationship issues; anger directed at or from women)
MOON inconjunct JUPITER (relationship issues; emotional discontent; can't get what he wants (Jupiter in Aries) because what he needs (Moon) is perfection (Virgo) --- (notice Jupiter conj. Chiron, contributing to the 'woundedness' of this aspect)
MOON semisquare SATURN (relationship issues; women are not to be 'trusted'; coldness towards women; offers love then takes it back; emotionally withdrawn)
MOON square NEPTUNE (delusion, especially in terms of women --- women aren't who they 'seem' to be; 'she's turned into an entirely different person!' or 'she wasn't like this when I married her!' scenario, etc.)
Just these small observations already paint a vivid red flag regarding JP's emotional/psychological make-up.
Also, please note JP was born on a cusp. If his true birth time is around 4:30 pm or later, he will be an Aquarius rather than Capricorn and his 00 Aquarius SUN would have been partile square the Part of DEATH (00 Taurus) in the 12:05 am 'Last Seen' chart I posted above.
Could he be the perp?
Absolutely.
Thanks,
Soulscape