They called each other "sweetheart," "hunny," "love" and "babe." Those affectionate names are found throughout 3,668 text messages between Jessica Newman and Kevin Rubletz, which capture the intimate relationship between on-again, off-again couple who shared a child together.

But if prosecutors are correct, that tenderness gave way to a "crime of passion" on the night of March 10, 2015, when Rubletz allegedly murdered Newman in his van and then dumped her body north of Calgary.

Jurors at Rubletz's second-degree murder trial were presented the text messages retrieved from Newman's iPhone by Const. Ian Whiffen, who is with the Calgary Police Service's digital forensics team. 

The messages span a one-year period from March 2014 to March 2015, during which time the couple is engaged, broken up and engaged again, all the while keeping what Whiffen characterized as a "loving tone" with each other. 

Jurors also viewed a photo of Newman's hand wearing an engagement ring. 

Court Exhibit Jessica Newman Kevin Rubletz

A court exhibit of a photo of Jessica Newman's hand wearing an engagement ring. (Court Exhibit)

In the days leading to her disappearance, Newman seemed ultimately hopeful she was about to get more time with her three-year-old boy. 

The following is an exchange between the two on March 4, 2015:

Newman: court is on the 11 right?
Rubletz: yep
Newman: We gonna go down together like last time?
Rubletz: lol yeah sure 
Newman: your still giving me 50/50 even tho your still at your sisters right?
Rubletz: Yeppers
Newman: Ok just making sure :)

On March 9, 2015, the day before Rubletz is accused of murdering Newman, the two woke up and exchanged I love yous before working out the details of Newman's visit with her son. They had even planned to attend a custody hearing together set for March 11, 2015, where Rubletz had planned to support Newman in her efforts to gain 50 per cent custody of their son.

Newman was last seen on March 10, 2015. When her body was found two months later in a rural ditch near Balzac, it was determined she had been stabbed 75 times.

Rubletz told police that on the night Newman disappeared, he had picked her up after work, took her for coffee and then dropped her at home around 9:30 p.m. 

But prosecutors Shane Parker and Tom Spark have a different theory. They believe Newman was sitting in the front seat of Rubletz's van when she was killed. Parker told jurors the evidence will show gouge marks on the seats and a "bloodletting event" took place in the van. Newman's DNA was also found in the vehicle.

On March 11, 2015, the day the former couple was due in court, Rubletz showed up; Newman, who was excited about the prospect of getting more time with her son, did not.

Under cross examination by defence lawyer Joshua Sutherland, Whiffen confirmed that in the messages he'd reviewed between the former couple he'd not seen any threats of violence by Rubletz toward Newman.

Jurors heard that Calgary police questioned Rubletz several times and noted changes in his version of events. 

The three-week jury trial is being presided over by Court of Queen's Bench Justice Glen Poelman. Rubletz is represented by defence lawyers Brendan Miller and Joshua Sutherland.