Although several neighbors in Sanford’s Retreat at Twin Lakes community placed 911 calls the night of Trayvon’s death, one particular call, from Jenna Lauer, captured several harrowing seconds of yelps followed by a single gunshot.

The “Lauer call,” as defense attorney Mark O’Mara referred to it, was played multiple times in court Monday so witnesses could say who they thought was screaming.

“There’s absolutely no doubt in my mind, that is George Zimmerman, and I wish to God I did not have that ability to understand that,” Donnelly testified. He said his experience as a U.S. Army medic in Vietnam taught him to identify screams in traumatic situations.

On cross-examination, Donnelly said he had given $4,700 in clothes, money and food to Zimmerman after the shooting. He also acknowledged that he had never heard Trayvon’s voice, which meant he was unlikely to have been able to identify it on the 911 recording.

Prosecutor Bernie de la Rionda countered O’Mara’s playing of the Lauer call by playing, on cross-examination, Zimmerman’s non-emergency call to police when he reported Trayvon as suspicious. In that call, Zimmerman uttered profanities that the state has argued showed ill-will, spite or hatred — elements of second-degree murder.

Jurors, who have heard the recordings about a dozen times during the trial, remained attentive but took only occasional notes as the audio played.

Trayvon’s parents stayed in the courtroom throughout the re-playing of the 911 call. Earlier in the trial, they had been leaving the room before the graphic tape was played.

On the witness stand Monday, Trayvon’s father said the sounds still haunt him.

“You realized that was the shot...” de la Rionda began to ask.

“That killed my son, yes,” Tracy Martin said.

“My world from that point and until today has just been turned upside down,” Martin continued. “I was listening to his last cry for help, listening to his life being taken, trying to come grips with the fact that Trayvon isn’t here...

“I was trying to figure out ... why did the defendant get out of his vehicle and chase my son?”

The judge’s ruling on the marijuana issued, made after jurors were dismissed for the day Monday, was a big win for the defense and a correct decision, legal experts said. A state’s witness, assistant medical examiner Dr. Shiping Bao, opened the door for the drug report last week when he revealed, outside the presence of jurors, that he believed the marijuana in Trayvon’s system could have had an effect on him that night.

The decision to allow testimony about the marijuana use was “not even close,” said Miami defense attorney Brian Tannebaum, because prosecutors have brought in so much of Zimmerman’s past, including his college courses, interest in law enforcement and physical training.

“What’s good for one side is good for another. It’s pretty clear,” Tannebaum said.

Former Miami-Dade prosecutor John Priovolos said that while the defense could make an argument that the teen’s use of marijuana made him aggressive, the evidence also could be seen as a significant blow to the credibility of a key state witness: Rachel Jeantel.

The Miami teen told jurors that she was on the phone with Trayvon moments before his death and heard him describe Zimmerman as a “creepy-ass cracker” who was following him.

“Their best bet is to say Trayvon is not a bad person because he was smoking dope, but his statements to Rachel that night might not be credible because of the drug use,” Priovolos said.