Holly Bobo's mother breaks down on stand as disturbing details emerge in murder trial

A man accused of kidnapping, raping and killing a Tennessee nursing student had "visible scratches" and a suspicious mattress outside his home in the days following Holly Bobo's disappearance, law enforcement officials testified Tuesday.

Jurors were also shown photos of Bobo's blood found inside the carport of her family's rural Tennessee home on the second day of testimony in the trial of 33-year-old Zachary Adams, who is accused of killing Bobo in April 2011.

Adams has pleaded not guilty to kidnapping, raping and murdering Bobo, who was 20 when she was last seen being led by a stranger into the woods near her home in Parsons on April 13, 2011. Her partial remains turned up near Adams’ home -- about 10 miles to the north -- in September 2014. If convicted, Adams faces the death penalty.

On Tuesday, Tennessee Highway Patrol trooper Warren Rainey recounted how he was first to question Adams about two weeks after Bobo disappeared. Adams had a criminal record that included drug possession and assault and he lived in an area near where a credit card receipt with Bobo's signature was found, Rainey said.

Rainey told jurors that Adams was "shaking" when he showed up unannounced at his home north of Parsons. The officer also said he discovered a mattress that appeared to be in good condition resting against the side of the house.

"When I saw the mattress it gave me the gut feeling of something is not right," Rainey told jurors inside the Hardin County Courthouse in Savannah, Tenn.

"I could tell he was visibly shaken. He was scared ... he was shaking," Rainey said of Adams.

An FBI agent also testified about fresh scratches found on Adams' arm after Bobo's disappearance. The agent described them as "linear scratches" on the inner arm -- prompting him to take photographs of the wounds, which were shown to jurors.

Earlier Tuesday, the court viewed photos of bloodstains found near Holly's Ford Mustang in the family’s garage on the day she disappeared. Special Agent Lawrence James, a forensic scientist with the Tennessee Bureau of Investigation, said DNA analysis showed that the 50 to 60 blood drops found on the floor of the carport belonged to Holly and indicated "there was some sort of struggle."

The hours-long testimony Tuesday followed an emotional first day of trial during which Holly's mother, Karen, collapsed on the stand when shown photos of her daughter's wallet and lunch purse.

In their opening arguments, prosecutors described chilling details: Adams, they said, asked his friend, Jason Autry, to help him dispose of Bobo's body after he had drugged and raped her. Thinking she was already dead, Adams told Autry he was going to "gut" Bobo's body so she would not float to the surface once they dumped her into the Tennessee River, according to the prosecution.

Bobo allegedly was wrapped in a blanket inside the vehicle -- but apparently she was still alive. She then made a noise and moved, prompting Adams to shoot her in the head, prosecutors claimed.

"Jason sees a blanket in the bed of Zach's truck. There’s a body in the blanket," assistant Shelby County District Attorney Paul Hagerman said in opening statements.

Hagerman told jurors that evidence and testimony will show Adams told Autry that he, Shayne Austin, and John Dylan Adams -- the defendant's brother -- had kidnapped and raped Holly. Austin was found dead of an apparent suicide in 2015.

Zachary Adams "took her. He raped her. He killed her. He discarded her. He covered it up. He bragged about it. And he almost got away with it," Hagerman said.

In all, six men were arrested for varying degrees of involvement in the death of Bobo — including Autry, who in July was offered federal immunity in exchange for his testimony against one of his co-defendants, according to court documents.

Jennifer Thompson, Adams’ defense attorney, said in her opening argument that her client is not guilty. She said Adams was charged after investigators interviewed several other men and they needed someone to blame.

Authorities found no hair, fingerprints or DNA belonging to Bobo in a search of Adams’ home before he was charged in 2014, Thompson said.

Thompson said Autry, who also is charged with kidnapping, raping and killing Bobo, gave investigators statements about the woman’s killing in return for a reduced charge.

"He basically sells his death penalty" to prosecutors, Thompson said of Autry. "There are real problems with his story."

Bobo, a nursing student at the University of Tennessee at Martin, who lived with her family in Decatur County, was last seen by her brother in the early morning of April 13, 2011.

Clint Bobo, then 25, reported seeing his sister being led by a man into the woods near their home at 7:30 a.m. Clint told investigators he initially assumed Holly was with her boyfriend, but said he grew concerned after finding blood outside, prompting him to call 911.

The three-year search for Bobo was exhaustive and the costliest in Tennessee state history. 

Before collapsing on the stand Monday, Karen Bobo described the panic she experienced upon learning her daughter had been kidnapped. She later listened as prosecutors played a recording of her own frantic 911 call in which she yelled at a dispatcher, "Someone in full camouflage has Holly."

"Everything was normal [that morning]," said Karen Bobo, who taught both Adams and Autry in school. "I told her goodbye and I loved her."

The Associated Press contributed to this report. 

Cristina Corbin is a Fox News reporter based in New York. Follow her on Twitter @CristinaCorbin.