SANTA MONICA, Calif. (AP) _ Bill Cosby and his family listened with jurors Monday as a prosecutor described Mikail Markhasev as the killer of Cosby's son, Ennis, and the defense said police arrested the wrong man.

Cosby and his family appeared in court for the first time during the trial as prosecutors and the defense presented closing arguments.

``Ennis Cosby had money, a beautiful car, a watch. ... The defendant saw an opportunity,'' Deputy District Attorney Anne Ingalls said. ``He goes up and tries to take property but gets spooked. ... He shoots the gun and runs away.''

Ennis Cosby, 27, a vacationing graduate student from Columbia University, was fatally shot Jan. 16, 1997, while changing a flat tire on a dark road in Sepulveda Pass.

Markhasev, a Ukrainian immigrant with a history of gang affiliations and a previous brush with the law, was arrested nearly two months later. He was charged with murder and robbery.

``When this all happened we were shocked about who was killed,'' Ingalls said, ``son of Mr. and Mrs. Cosby, someone we all grew up with. ... The randomness of this crime. If we were to pull over with a flat tire do we have a bull's eye on our back for a predator?''

With the case expected to go to the jury late in the day, defense attorney Harriet Hawkins urged jurors ``not to consider the media coverage and the celebrity of Ennis Cosby's family. ... It's not just your gut reaction. You have to look at the evidence and questions raised by the evidence.''

Hawkins and attorney Henry Hall pointed out what was missing from the prosecution's case _ fingerprints, eyewitness identification and any evidence putting Markhasev at the scene of the crime.

The lawyers attacked the testimony of informant Christopher So, who led police to where the gun was found, and said jurors would be accepting the word of a convicted felon who sold his story to The National Enquirer if they were to convict Markhasev.

Bill Cosby sat with his wife, Camille, in a front row of the courtroom, flanked by two daughters, Erika and Erinn. They sat directly next to Markhasev's mother, grandmother and cousin.

Ingalls said that the 19-year-old defendant essentially had convicted himself with letters he wrote in jail referring to details of the crime.

``The letters are everything in this case,'' Ingalls said, and went on to read statements such as: ``It was a robbery gone bad.''

She pieced together elements of her case with the help of an elaborate chart, pointing arrows of guilt toward the defendant. She showed Markhasev's picture next to a composite drawing of the killer and said, ``That is the defendant.''

During the trial, the defense suggested that police arrested the wrong man and pointed the finger at Eli Zakaria, one of two other people with Markhasev at the time. The defense also keyed on reward money a prosecution witness was seeking from a tabloid.

The prosecution presented only one eyewitness from the killing scene. Stephanie Crane, who said she had a date with Ennis Cosby, could not identify Markhasev.

The prosecution also presented a gun found wrapped in knit cap and linked to Markhasev by the DNA of a single tiny hair.

The man who led police to the area where the gun was found testified that while helping Markhasev search for that gun he heard Markhasev tell another friend, ``I shot a nigger. It's all over the news. It's big.''