Four more witnesses took the stand today for a total of 40 so far. The most disturbing testimony of the day comes from David Brani whose heat study suggests that Cooper may have still been alive at 12:45 pm on June 18, 2014 when Harris threw a bag with some just-purchased light bulbs in the front seat of the car. Jurors also heard from a woman who was sexting with Harris while Cooper was dying.

37. David Brani, mechanical engineer, thermal dynamics, conducted a heat study of the car

Brani works for Works for ATS tech services. At the outset, Brani discussed refrigeration systems and the nature of heat transfer in the world of thermal dynamics.

Outside of this specific case, he has not studied temperature rising in a vehicle. He reviewed general literature before going to the field to test in this case on July 8, 2014—the day he tested at the Home Depot Treehouse location.

The purpose was to determine the temperature inside the vehicle throughout the day. He used 12 thermal measuring devices throughout the car and near the car seat. Secondary data were recorded such as continuous monitoring of heat and humidity, wind speed, use of a light meter (measures intensity of the sun every hour), and constant video recording of the vehicle throughout the day (how much sunshine, partial shade was on the car). He took photos, too.

The highest outdoor temp on July 8, 2014 was 92 degrees, one degree difference from June 18, 2014. Brani went through various times of day between the two days—the temperature varied about 1-2 degrees throughout the day. Around midday the car was in and out of sun and shade. For a few hours in the afternoon, it was in direct sunlight.

At 12:45 pm, the car seat was 98 degrees; outside it was 88 degrees. (Is it possible Cooper was alive when Harris threw the bag of light bulbs in the car at the hour?) The first time the interior temperature rose above 100 degrees was shortly before 1:00 pm. The temperature inside the car peaked at 125 degrees at 3:30 pm in Brani’s study.

On cross, the defense pointed out that Brani was paid for his work at $295/hour for a total of about $24,000. The defense focused on factors that may have affected the interior temperature (such as humidity from a child inside) that were not replicated in the study. Brani did not think Cooper’s body would have significantly affected the temperature.

38. Lauren Jamar, Director of Content Operations for Whisper App

As the custodian of records, Jamar simply identified records of the anonymous app, Whisper, that her employer provided to the prosecution. Jamar also explained to jurors how Whisper monitors texts and users; they do no save private chats.

39. Caitlin Floyd, sexting with Harris before and day of Cooper’s death

Floyd chatted with Harris on the Whisper and Kik apps. She asked him if he was married and if he had a conscience. He said no and also said he “likes risky.” (She was single then but is now married.)

On the morning of June 18, 2014, Harris sent her inappropriate photos. She asked him if he was alone and he said he was not.

Harris asked her to send a pic of her breasts at 1:00 pm on the day Cooper died.

In the days prior to Cooper’s death, Harris said he was happily married except for the sex. He also texted: “I’m so horny.”

40. Ronson Bridges Smith, Detective, Cobb County PD, High Tech Crimes Unit

Det. Smith had secured the video of Harris holding Cooper at the Chik-fil-A that day. Jurors saw the video. Smith identified content from Harris’s phone on June 18, 2014.

At 9:15 am, Harris texted: “I love my son and all but we both need escapes.” (This was sent 15 minutes after he was seen at Chik-fil-A.

That morning, Harris commented on this post: “I hate being married with kids. The novelty has worn off and I have nothing to show for it.”

On cross, the defense pointed out that Harris researched costs for a child’s passport because he was planning a cruise.

Det. Smith was still on the stand when court broke for the day. His testimony will resume at 8:30 am ET tomorrow.