Prosecutors trying former Minneapolis police officer Derek Chauvin in George Floyd's death called their last witnesses Monday, including one of Floyd's younger brothers, who broke down in tears as he testified about their childhood in Texas.

While prosecutors have not yet officially rested their case, they are not expected to call any more witnesses following 11 days of testimony. Hennepin County District Judge Peter Cahill told jurors Chauvin's defense is expected to begin calling its witnesses Tuesday.

The defense could finish its case by Thursday, Cahill said, adding that the court would likely take Friday off and resume next Monday with closing arguments from both sides. Jurors will be sequestered for deliberations.

Philonise Floyd, 39, testified in the early afternoon about his oldest brother, who served as the family's leader and a beacon of influence in their housing complex in Houston.

"George, he would always be up on our mom," Philonise Floyd said. "He was a big mama's boy. … Every mother loves all of her kids but it's so unique how they were. He would lay up on her like in the fetus position like he was in the womb."

A bystander's video of Floyd's May 25 arrest captured Floyd pleading for breath and calling out "Mama" a few times as Chauvin knelt on his neck for more than nine minutes while he lay handcuffed, stomach-down in the street. Former officers J. Alexander Kueng knelt on his buttocks and Thomas Lane held onto his legs as Tou Thao kept angry bystanders at bay.

Chauvin is on trial on charges of second-degree murder, third-degree murder and second-degree manslaughter. Kueng, Lane and Thao are scheduled to be tried Aug. 23 on charges of aiding and abetting second-degree murder and manslaughter.

All four defendants, who were fired, are out on bond.

Philonise Floyd broke into tears when a photo of their mother holding Floyd as a baby was shown to the jury.

"He loved her so dearly," he said, adding that his brother taught the family how to love and respect their mother. "… I miss both of them."

Philonise Floyd was emotional as he told the court that his wedding anniversary is May 24, a day before his brother died and six days before their mother died three years ago.

"It's like a bittersweet month, because I'm supposed to be happy when that month comes," he said.

Floyd, who had moved from Texas to Minnesota years before, spoke to their mother on the phone while she was in hospice care but didn't see her before she died on May 30, 2018, Philonise Floyd said. Floyd repeatedly called out "Mama" to her at her funeral and wouldn't leave the casket, he testified. Her funeral was the last time the brothers saw each other in person, although they kept in touch afterward.

In their Texas housing complex, Philonise Floyd said, his brother "was one of those people in the community, when they had church outside, people would attend church just because he was there. Nobody would go out there until they seen him. He was a person everybody loved around the community. He just knew how to make people feel better."

Philonise Floyd frequently spent time with his brother "playing video games all the time" as children despite an approximately seven-year age gap.

"George, also, he used to make the best banana mayonnaise sandwiches … because George, he couldn't cook. He couldn't boil water," Philonise Floyd testified, adding that his brother made sure everyone at home had something to eat despite an absence of cooking skills.

Marks on a wall in the family home tracked Floyd's growth. "He wanted to be taller all the time because he loved sports," Philonise Floyd said. "He wanted to be the best."

In an interview last week with the Star Tribune, Philonise Floyd reflected on the approaching anniversary of his brother's death.

"I know God was there …" he said. He recounted how several strangers converged at the scene of his brother's arrest in south Minneapolis and became integral to the prosecution's case, among them: Donald Williams Jr., a trained martial arts fighter who testified about the impact of Chauvin's knee on Floyd's neck; Darnella Frazier, who recorded the incident and shared it online with the world; Judeah Reynolds, then 9, who wore a shirt emblazoned with "Love" across the front; and off-duty Minneapolis firefighter Genevieve Hanson, who tried to intervene but was rebuffed by the officers.

"That'll be seared in all of their minds forever," Philonise Floyd said of the officers' response to Hanson's offer of help.

The high number of civilian witnesses to Floyd's death is unusual for killings involving police in Minnesota, which are rarely prosecuted. Floyd's death is the fourth time officers have been charged in the state with killing a civilian on the job.

Testimony began Monday with cardiologist Dr. Jonathan Rich, a medical expert from Northwestern Memorial Hospital in the Chicago area. The prosecution called him to counter defense contentions that Floyd died from health problems and illicit drug use.

The Hennepin County Medical Examiner's Office ruled Floyd's cause of death "cardiopulmonary arrest complicating law enforcement subdual, restraint, and neck compression." The office also listed hardening and thickening of the artery walls, heart disease and drug use as "other significant conditions." Fentanyl and methamphetamine were found in Floyd's system.

"I believe that Mr. George Floyd's death was absolutely preventable," Rich testified.

Rich said he believes Floyd died of cardiopulmonary arrest caused by low oxygen levels that were "induced by the prone restraint and positional asphyxia that he was subjected to."

Further, the doctor said, "I can state with a high degree of medical certainty that George Floyd did not die from a cardiac event and he did not die from an overdose."

The doctor agreed that Floyd had a significant presence of heart disease but tried to fend off defense attorney Eric Nelson's questions about the dangers of narrowed arteries by noting that the heart builds new paths for blood to circulate under such conditions.

Academic use-of-force expert and former police officer Seth W. Stoughton, of the University of South Carolina Law School was the prosecution's last witness.

Stoughton walked through several video clips of Floyd's arrest and said he never should have been placed stomach-down on the pavement.

Floyd told officers "thank you" for being removed from the squad car and put on his knees, he testified, and was never a flight risk or a threat to the officers' safety.

"No reasonable officer would have believed that [the restraint used on Floyd] was appropriate, acceptable or reasonable force," he testified.

Nelson attempted to raise doubts about Stoughton's analysis by noting that he had the luxury of hindsight and reviewed arrest videos in slow motion. Under cross-examination, Stoughton agreed that officers are allowed to use force based on the "totality of the circumstances."

"… The suspect does not get to dictate, 'Do I get to sit on the ground,' or, 'Do I get to sit in the squad car?' " Nelson asked, referring to Floyd's refusal to get into the back seat of a squad car before he was forced in, fell out the other side and ended up on the street.

"Yes," Stoughton eventually answered.