As the George Huguely murder trial moved into day four, prosecutors continued to lay out their explanation of what happened the night Yeardley Love died.

Prosecutors called police officers and emergency medical technicians to the stand.

K.W. Blackwell:

The first witness of the day was K.W. Blackwell of the Charlottesville Police Department. He described what he saw when he responded to the scene around 2:20 a.m. He said Love was on her back and he started CPR. That's when he noticed Love's face was bloody, and she had a black eye. He told the court that was when he realized the situation was not a case of alcohol poisoning, which is how the response call came in. The defense questioned him about the layout of the room and asked about Love's body temperature.

Michael Hanshew:

The next witness was Michael Hanshew, an EMT with Charlottesville-Albemarle Rescue Squad. He was the first EMT to arrive at Love's apartment. Commonwealth's Attorney Dave Chapman showed pictures of what the EMTs did to Love upon arrival, allowing him to confirm those images.

The EMT told the court that crews spent approximately 25 minutes in resuscitation efforts until they asked for authorization to discontinue. He said Love never exhibited any signs of life.

Upon cross-examination, defense attorney Rhonda Quagliana asked him to stand and show how to perform CPR. Lawrence also asked him about the side effects of intense, long CPR efforts, specifically if CPR can make a prior wound bleed and if the blood would spatter around the room. Hanshew said he has not seen bruising cause by CPR, but he has seen open wounds start to bleed again.

Dr. William J. Brady:

Another witness for the prosecution was Dr. William J. Brady, a UVA physician and professor in emergency medicine and the medical director for the Charlottesville - Albemarle Rescue Squad.

The prosecution spent time working to establish the doctor's strong credentials in cardiac arrest and cardiovascular issues in the emergency field. The prosecution says he is a CPR expert who reviewed many reports in this case, including the autopsy report.

He explained the science behind cardiac arrest and what the standards are when EMTs arrive on scene.

The defense's cross-examination honed in on blood flow during CPR and what damage it might cause to the brain, but made a point to say he is not a brain expert. His testimony lasted just under an hour.

Detective Shawn Bayles:

Next on the stand was Detective Shawn Bayles from the Charlottesville Police Department. He was the detective on duty when Love was found.

Bayles testified to seeing a large hole in the door and asked rescue crews if forced entry was required. He then said he requested a camera after he saw Love's injuries, that in his experience looked like she was "victim of some sort of violence." Bayles said he told EMTs that they "were now part of an active crime scene."

The pictures he took were shown to the jury during his testimony. He also said a female EMT brought it to his attention that the toilet set was left up, but only girls lived in the apartment.

Bayles stepped down prior to the lunch break but may be called back to the stand at a later time.

Dr. Danny Mistry:

After the lunch recess, Dr. Danny Mistry, a primary care physician for UVA athletes in 2010, took the stand. He explained his doctor-patient relationship with Love and confirmed a prescription for adderall to treat Attention Deficit Disorder. He says this can induce a change in heart rhythm, but an electrocardiogram (EKG), for Love showed normal heart activity.

Mistry also said all athletes using adderall went through extra heart screenings. He said the last time he saw Love was a week before her death when she stopped to say, "thank you for the four years." He says she was in good shape at that time, and told the court there was no medical reason why Yeardley Love should have died on May 3rd of 2010.

Several of George Huguely's friends and fellow lacrosse players testified that Huguely had a growing drinking problem in 2010, to the point where they were going to attempt an intervention. They also spoke about an incident in February of 2010 where someone caught Huguely choking Love in his bedroom.

Michael Burns:

Former University of North Carolina lacrosse player Michael Burns took the stand. He told the court he first met Yeardley Love at the Preakness horse race while among friends with other lacrosse players at UVA including George Huguely. He recounted that incident in February 2010 and recalled hearing "help me" from outside Huguely's apartment. He said he witnessed Huguely with his arms in a choking position around Love's neck. He demonstrated the choking position for the court and told the defense, "I can answer with all honesty his hand was around her neck." Burns admitted he was in a romantic relationship with Love, saying they "hooked up" from time to time. The defense team defined "hooking up" to court as intimate contact up to or including sex.

Tim Fuchs:

Former UVA lacrosse player Tim Fuchs testified about the extent he knew Burns and Love. He recounted what he remembered from that same incident at Huguely's apartment. He said he was behind Burns was the door was open, saying Love "looked scared" as she left the room. He also talked about Huguely's drinking during a father/son golf tournament the Sunday before Love's death. He said Huguely was "drunk, making inappropriate comments."

Bryan Carroll:

Bryan Carroll took the stand next. His twin brother lived with Huguely in 2010. He testified that Huguely told him that he was trying to talk to Love during what others perceived was a choking incident. Carroll also confirmed Huguely was drinking throughout the golf tournament, and said Huguely was, "slurring words and interrupting parents." When asked about Huguely's drinking habits, Carroll says he drank "about four times a week."

Kate Kamber:

The prosecution called Kate Kamber, UVA student, to the stand next. She recounted an incident a week before Love's death while two friends were visiting. She said that those two friends went back to Huguely apartment while Kamber wrapped up work at a bar. When she went to pick up the girls, Love walked into the apartment and "scolded" him. Kamber says Love raised her voice and asked Huguely, "are these the girls you've been texting?" She said Huguely looked startled and embarrassed, and that Huguely was doing a favor by letting the girls come back with him. Kamber said they were sitting on separate couches when she came into the apartment.

Elizabeth McLean:

Love's sorority sister and UVA student Elizabeth McLean testified next. She was dating Huguely's roommate in 2010. McLean says she was in the apartment when the incident with the girls occurred. She says she heard them leave, then Huguely and Love "bickering." Then, she said she heard Love hit Huguely with her purse. She told the court Huguely yelled stop, and the contents of Love's purse spilled onto the floor. She helped gather Love's belongings and confirmed Love "had been drinking" and was angry when she left. She said they could not locate Love's phone or camera at the time.

When the prosecution asked about the choking incident in February 2010, McLean said she was on the stairwell, where Love spoke to her. She said Love was "upset, crying (and) holding her chest" after the incident. When asked about Huguely's drinking habits, She told the court, "his excessive drinking had become an issue."

Stephanie Aladj:

The next witness was another sorority sister and UVA student, Stephanie Aladj. She said that Love was upset at one point because she was in an "on and off" romantic relationship with Huguely. When asked if she know about the relationship between Huguely and Love, she told the court that Huguely told her, he and Love were "on and off." Aladj said she thought she and Love "cleared the air" in fall 2009.

Aladj testified that she saw Huguely during the early morning hours in the week before Love's death. She said Huguely also contacted her via text Saturday before Love's death, and she had a missed call from him early Sunday morning.

Detective Albert Leightly:

Testimony shifted back to the technical when computer forensics expert, Detective Albert Leightly took the stand. He described for the prosecution the imaging process he goes through to search a computer. He explained finding "fragments" of emails between Huguely and Love. He explained the UVA email system and showed email remnants he recovered. That included the email remnant that said, "I should have killed you" dated April 30 just before 9 p.m.

Michael Fisher:

After a short recess, FBI electronics analyst Michael Fisher took the stand to explain how he searches a phone for information. Fisher never identified the owner of a Blackberry phone he was given to recover, but confirmed email communication between Huguely and Love.

James Mooney:

Police officer James Mooney then took the stand to explain how he and two other detectives recovered Love's computer from a dumpster near Huguely's apartment. He pointed out the location of the dumpster on a map. At this point, the prosecution showed pictures of the dumpster and confirmed Lover's computer was there. Mooney also spoke about whether emails are "permanent" on UVA accounts.

Molly Millard:

Love's last roommate before her death and former UVA lacrosse player, Molly Millard, took the stand next, recalling the emails through tears. Millard told the court, Love read emails from Huguely out loud in their room and referred to the "I should have killed you" statement.

Day four of the murder trail adjourned for the day around 6:15 p.m.  There were 17 witnesses that took the stand Thursday.  The trial will resume with more testimony from the prosecution Friday at 9 a.m.

We will continue to bring you the latest. Follow @NBC29Huguely for continuous updates from the courtroom throughout the day.