Aaron Hernandez murder trial: Defense argues friends may have done it

Defense attorneys for ex-NFL star Aaron Hernandez rested their case on Monday in his murder trial after calling three witnesses including a drugs expert and two forensics analysts.

The drugs expert, Dr. David Greenblatt of Tufts University School of Medicine, said that PCP - a drug an earlier witness said may have been used by people who were with Hernandez at the time of the murder - could trigger violent behavior.

The forensics analysts said Hernandez's DNA was found on a piece of chewing gum stuck to a shell casing retrieved from the trash by investigators, with one saying the DNA could have been transferred to the shell from the gum.

The testimony played into the defense team's arguments that Hernandez's friends may have committed the killing, and not the former New England Patriots tight end himself.

Hernandez has pleaded not guilty to the murder of Odin Lloyd, a semiprofessional football player who was dating the sister of Hernandez's fiancée. If convicted, he faces a maximum penalty of life in prison.

Prosecutors say Hernandez and two friends, Ernest Wallace and Carlos Ortiz, picked up Lloyd at his Boston home in the early hours of June 17, 2013, and shot him to death in an industrial park near Hernandez's house in North Attleboro, Massachusetts.

Prosecutors called more than 120 witnesses in the trial, which began in late January. Closing statements will begin Tuesday before the jury deliberates.

On Monday, Dr. Greenblatt testified that PCP, or angel dust, can make people sweaty or shaky, and hinder cognition. "It can cause violent behavior," he told jurors.

Earlier in the trial, Jennifer Mercado, a cousin of Hernandez, testified that Wallace and Ortiz appeared jittery and sweaty when she saw them before the murder. She said they behaved similarly to when they had used PCP previously.

Wallace and Ortiz have also been charged with murder and will be tried separately. They have pleaded not guilty.

Later on Monday, Eric Carita, a private forensic consultant, testified that he swabbed a piece of chewed gum that was stuck to an empty shell casing and had been removed from a rental car returned by Hernandez after the murder.

Jennifer Smith, who works for a private DNA testing lab, also testified a swab from the gum matched the DNA profile of Hernandez. She said "it is extremely likely some of the saliva that was in that gum was transferred to that casing."

(Editing by Richard Valdmanis, David Gregorio and Ted Botha)