SAN DIEGO — An 18-year-old accused of killing an elderly homeless man pleaded not guilty in a San Diego courtroom one week after the attack.

Daniel Ruben Martin of El Cajon faces one count of murder and faced a judge for the first time Wednesday.

San Diego police say Martin and another teen are accused of beating and killing 65-year-old Michael Shook. Shook had been homeless and was found dead in the early morning hours on July 5 in Bonita Cove Park on West Mission Bay Drive.

Martin is being held without bail.

“It’s hard, it’s hard to find out the details about how heinous the attack actually was,” Michael A. Shook, the victim’s son, said.

He said he had already been grieving the loss of his father, but when police told him how he died, he was in shock.

The victim’s son was in the courtroom Wednesday. He shared his father’s name and brought more insight to the man he was. He said he grew up in Vista with his mother and father, and his father was an avid fisherman. He said his father got into trouble later in life, and after he was released from custody, he was homeless and had terminal cancer.

“It’s very sad because he was kind of right there on his way out, and no one really deserves to die in that type of manner. It’s kind of more sad that these kids threw away a big chunk of their lives and made their family members victim, too. You could have just left the homeless man on the bench,” Michael A. Shook said.

Authorities said when they arrived to the scene early Wednesday, they found Shook had multiple stab wounds to his upper body and injuries to his face that indicated he had been beaten.

Police said during their initial investigation, they discovered the victim was in a physical confrontation with a group of five or six people in their late teens and early twenties.

Three days after the attack, authorities arrested Martin during a traffic stop. On Sunday, a 17-year-old surrendered to police at San Diego Police Department Headquarters, but that person’s identity has not been released because they are a minor.

Martin will be back in the courtroom July 21 for a bail review, during which more details on the case are expected to be discussed.

Martin’s family was in the courtroom but declined to do an interview Wednesday.